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Unhappy Trails
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HAARP patents
 Tue Aug 20, 2002 10:11 am
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United States Patent 4,686,605
Eastlund August 11, 1987
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Method and apparatus for altering a region in the earth's atmosphere, ionosphere, and/or magnetosphere
Abstract
A method and apparatus for altering at least one selected region which normally exists above the earth's surface. The region is excited by electron cyclotron resonance heating to thereby increase its charged particle density. In one embodiment, circularly polarized electromagnetic radiation is transmitted upward in a direction substantially parallel to and along a field line which extends through the region of plasma to be altered. The radiation is transmitted at a frequency which excites electron cyclotron resonance to heat and accelerate the charged particles. This increase in energy can cause ionization of neutral particles which are then absorbed as part of the region thereby increasing the charged particle density of the region.
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Inventors: Eastlund; Bernard J. (Spring, TX)
Assignee: APTI, Inc. (Los Angeles, CA)
Appl. No.: 690333
Filed: January 10, 1985
Current U.S. Class: 361/231; 89/1.11; 244/158R; 380/59
Intern'l Class: H05B 006/64; H05C 003/00; H05H 001/46
Field of Search: 361/230,231 244/158 R 376/100 89/1.11 380/59
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References Cited [Referenced By]
Other References
Liberty Magazine, (2/35) p. 7 N. Tesla.
New York Times (9/22/40) Section 2, p. 7 W. L. Laurence.
New York Times (12/8/15) p. 8 Col. 3.
Primary Examiner: Cangialosi; Salvatore
Attorney, Agent or Firm: MacDonald; Roderick W.
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Claims
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I claim:
1. A method for altering at least one region normally existing above the earth's surface with electromagnetic radiation using naturally-occurring and diverging magnetic field lines of the earth comprising transmitting first electromagnetic radiation at a frequency between 20 and 7200 kHz from the earth's surface, said transmitting being conducted essentially at the outset of transmission substantially parallel to and along at least one of said field lines, adjusting the frequency of said first radiation to a value which will excite electron cyclotron resonance at an initial elevation at least 50 km above the earth's surface, whereby in the region in which said electron cyclotron resonance takes place heating, further ionization, and movement of both charged and neutral particles is effected, said cyclotron resonance excitation of said region is continued until the electron concentration of said region reaches a value of at least 10.sup.6 per cubic centimeter and has an ion e!
nergy of at least 2 ev.
2. The method of claim 1 including the step of providing artificial particles in said at least one region which are excited by said electron cyclotron resonance.
3. The method of claim 2 wherein said artificial particles are provided by injecting same into said at least one region from an orbiting satellite.
4. The method of claim 1 wherein said threshold excitation of electron cyclotron resonance is about 1 watt per cubic centimeter and is sufficient to cause movement of a plasma region along said diverging magnetic field lines to an altitude higher than the altitude at which said excitation was initiated.
5. The method of claim 4 wherein said rising plasma region pulls with it a substantial portion of neutral particles of the atmosphere which exist in or near said plasma region.
6. The method of claim 1 wherein there is provided at least one separate source of second electromagnetic radiation, said second radiation having at least one frequency different from said first radiation, impinging said at least one second radiation on said region while said region is undergoing electron cyclotron resonance excitation caused by said first radiation.
7. The method of claim 6 wherein said second radiation has a frequency which is absorbed by said region.
8. The method of claim 6 wherein said region is plasma in the ionosphere and said second radiation excites plasma waves within said ionosphere.
9. The method of claim 8 wherein said electron concentration reaches a value of at least 10.sup.12 per cubic centimeter.
10. The method of claim 8 wherein said excitation of electron cyclotron resonance is initially carried out within the ionosphere and is continued for a time sufficient to allow said region to rise above said ionosphere.
11. The method of claim 1 wherein said excitation of electron cyclotron resonance is carried out above about 500 kilometers and for a time of from 0.1 to 1200 seconds such that multiple heating of said plasma region is achieved by means of stochastic heating in the magnetosphere.
12. The method of claim 1 wherein said first electromagnetic radiation is right hand circularly polarized in the northern hemisphere and left hand circularly polarized in the southern hemisphere.
13. The method of claim 1 wherein said electromagnetic radiation is generated at the site of a naturally-occurring hydrocarbon fuel source, said fuel source being located in at least one of northerly or southerly magnetic latitudes.
14. The method of claim 13 wherein said fuel source is natural gas and electricity for generating said electromagnetic radiation is obtained by burning said natural gas in at least one of magnetohydrodynamic, gas turbine, fuel cell, and EGD electric generators located at the site where said natural gas naturally occurs in the earth.
15. The method of claim 14 wherein said site of natural gas is within the magnetic latitudes that encompass Alaska.
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Description
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DESCRIPTION
1. Technical Field
This invention relates to a method and apparatus for altering at least one selected region normally existing above the earth's surface and more particularly relates to a method and apparatus for altering said at least one region by initially transmitting electromagnetic radiation from the earth's surface essentially parallel to and along naturally-occurring, divergent magnetic field lines which extend from the earth's surface through the region or regions to be altered.
2. Background Art
In the late 1950's, it was discovered that naturally-occuring belts exist at high altitudes above the earth's surface, and it is now established that these belts result from charged electrons and ions becoming trapped along the magnetic lines of force (field lines) of the earth's essentially dipole magnetic field. The trapped electrons and ions are confined along the field lines between two magnetic mirrors which exist at spaced apart points along those field lines. The trapped electrons and ions move in helical paths around their particular field lines and "bounce" back and forth between the magnetic mirrors. These trapped electrons and ions can oscillate along the field lines for long periods of time.
In the past several years, substantial effort has been made to understand and explain the phenomena involved in belts of trapped electrons and ions, and to explore possible ways to control and use these phenomena for beneficial purposes. For example, in the late 1950's and early 1960's both the United States and U.S.S.R. detonated a series of nuclear devices of various yields to generate large numbers of charged particles at various altitudes, e.g., 200 kilometers (km) or greater. This was done in order to establish and study artifical belts of trapped electrons and ions. These experiments established that at least some of the extraneous electrons and ions from the detonated devices did become trapped along field lines in the earth's magnetosphere to form artificial belts which were stable for prolonged periods of time. For a discussion of these experiments see "The Radiation Belt and Magnetosphere", W. N. Hess, Blaisdell Publishing Co., 1968, pps. 155 et sec.
Other proposals which have been advanced for altering existing belts of trapped electrons and ions and/or establishing similar artificial belts include injecting charged particles from a satellite carrying a payload of radioactive beta-decay material or alpha emitters; and injecting charged particles from a satellite-borne electron accelerator. Still another approach is described in U.S. Pat. No. 4,042,196 wherein a low energy ionized gas, e.g., hydrogen, is released from a synchronous orbiting satellite near the apex of a radiation belt which is naturally-occurring in the earth's magnetosphere to produce a substantial increase in energetic particle precipitation and, under certain conditions, produce a limit in the number of particles that can be stably trapped. This precipitation effect arises from an enhancement of the whistler-mode and ion-cyclotron mode interactions that result from the ionized gas or "cold plasma" injection.
It has also been proposed to release large clouds of barium in the magnetosphere so that photoionization will increase the cold plasma density, thereby producing electron precipitation through enhanced whistler-mode interactions.
However, in all of the above-mentioned approaches, the mechanisms involved in triggering the change in the trapped particle phenomena must be actually positioned within the affected zone, e.g., the magnetosphere, before they can be actuated to effect the desired change.
The earth's ionosphere is not considered to be a "trapped" belt since there are few trapped particles therein. The term "trapped" herein refers to situations where the force of gravity on the trapped particles is balanced by magnetic forces rather than hydrostatic or collisional forces. The charged electrons and ions in the ionosphere also follow helical paths around magnetic field lines within the ionosphere but are not trapped between mirrors, as in the case of the trapped belts in the magnetosphere, since the gravitational force on the particles is balanced by collisional or hydrostatic forces.
In recent years, a number of experiments have actually been carried out to modify the ionosphere in some controlled manner to investigate the possibility of a beneficial result. For detailed discussions of these operations see the following papers: (1) Ionospheric Modification Theory; G. Meltz and F. W. Perkins; (2) The Platteville High Power Facility; Carrol et al.; (3) Arecibo Heating Experiments; W. E. Gordon and H. C. Carlson, Jr.; and (4) Ionospheric Heating by Powerful Radio Waves; Meltz et al., all published in Radio Science, Vol. 9, No. 11, November, 1974, at pages 885-888; 889-894; 1041-1047; and 1049-1063, respectively, all of which are incorporated herein by reference. In such experiments, certain regions of the ionosphere are heated to change the electron density and temperature within these regions. This is accomplished by transmitting from earth-based antennae high frequency electromagnetic radiation at a substantial angle to, not parallel to, the ionosphere's !
magnetic field to heat the ionospheric particles primarily by ohmic heating. The electron temperature of the ionosphere has been raised by hundreds of degrees in these experiments, and electrons with several electron volts of energy have been produced in numbers sufficient to enhance airglow. Electron concentrations have been reduced by a few percent, due to expansion of the plasma as a result of increased temperature.
In the Elmo Bumpy Torus (EBT), a controlled fusion device at the Oak Ridge National Laboratory, all heating is provided by microwaves at the electron cyclotron resonance interaction. A ring of hot electrons is formed at the earth's surface in the magnetic mirror by a combination of electron cyclotron resonance and stochastic heating. In the EBT, the ring electrons are produced with an average "temperature" of 250 kilo electron volts or kev (2.5.times.10.sup.9 K) and a plasma beta between 0.1 and 0.4; see, "A Theoretical Study of Electron--Cyclotron Absorption in Elmo Bumpy Torus", Batchelor and Goldfinger, Nuclear Fusion, Vol. 20, No. 4 (1980) pps. 403-418.
Electron cyclotron resonance heating has been used in experiments on the earth's surface to produce and accelerate plasmas in a diverging magnetic field. Kosmahl et al. showed that power was transferred from the electromagnetic waves and that a fully ionized plasma was accelerated with a divergence angle of roughly 13 degrees. Optimum neutral gas density was 1.7.times.10.sup.14 per cubic centimeter; see, "Plasma Acceleration with Microwaves Near Cyclotron Resonance", Kosmahl et al., Journal of Applied Physics, Vol. 38, No. 12, Nov., 1967, pps. 4576-4582.
DISCLOSURE OF THE INVENTION
The present invention provides a method and apparatus for altering at least one selected region which normally exists above the earth's surface. The region is excited by electron cyclotron resonance heating of electrons which are already present and/or artifically created in the region to thereby increase the charged particle energy and ultimately the density of the region.
In one embodiment this is done by transmitting circularly polarized electromagnetic radiation from the earth's surface at or near the location where a naturally-occurring dipole magnetic field (force) line intersects the earth's surface. Right hand circular polarization is used in the northern hemisphere and left hand circular polarization is used in the southern hemisphere. The radiation is deliberately transmitted at the outset in a direction substantially parallel to and along a field line which extends upwardly through the region to be altered. The radiation is transmitted at a frequency which is based on the gyrofrequency of the charged particles and which, when applied to the at least one region, excites electron cyclotron resonance within the region or regions to heat and accelerate the charged particles in their respective helical paths around and along the field line. Sufficient energy is employed to cause ionization of neutral particles (molecules of oxygen, nitrog!
en and the like, particulates, etc.) which then become a part of the region thereby increasing the charged particle density of the region. This effect can further be enhanced by providing artificial particles, e.g., electrons, ions, etc., directly into the region to be affected from a rocket, satellite, or the like to supplement the particles in the naturally-occurring plasma. These artificial particles are also ionized by the transmitted electromagnetic radiation thereby increasing charged particle density of the resulting plasma in the region.
In another embodiment of the invention, electron cyclotron resonance heating is carried out in the selected region or regions at sufficient power levels to allow a plasma present in the region to generate a mirror force which forces the charged electrons of the altered plasma upward along the force line to an altitude which is higher than the original altitude. In this case the relevant mirror points are at the base of the altered region or regions. The charged electrons drag ions with them as well as other particles that may be present. Sufficient power, e.g., 10.sup.15 joules, can be applied so that the altered plasma can be trapped on the field line between mirror points and will oscillate in space for prolonged periods of time. By this embodiment, a plume of altered plasma can be established at selected locations for communication modification or other purposes.
In another embodiment, this invention is used to alter at least one selected region of plasma in the ionosphere to establish a defined layer of plasma having an increased charged particle density. Once this layer is established, and while maintaining the transmission of the main beam of circularly polarized electromagnetic radiation, the main beam is modulated and/or at least one second different, modulated electromagnetic radiation beam is transmitted from at least one separate source at a different frequency which will be absorbed in the plasma layer. The amplitude of the frequency of the main beam and/or the second beam or beams is modulated in resonance with at least one known oscillation mode in the selected region or regions to excite the known oscillation mode to propagate a known frequency wave or waves throughout the ionosphere.
BRIEF DESCRIPTION OF THE DRAWINGS
The actual construction, operation, and apparent advantages of this invention will be better understood by referring to the drawings in which like numerals identify like parts and in which:
FIG. 1 is a simplified schematical view of the earth (not to scale) with a magnetic field (force) line along which the present invention is carried out;
FIG. 2 is one embodiment within the present invention in which a selected region of plasma is raised to a higher altitude;
FIG. 3 is a simplified, idealized representation of a physical phenomenon involved in the present invention; and
FIG. 4 is a schematic view of another embodiment within the present invention.
FIG. 5 is a schematic view of an apparatus embodiment within this invention .
BEST MODES FOR CARRYING OUT THE INVENTION
The earth's magnetic field is somewhat analogous to a dipole bar magnet. As such, the earth's magnetic field contains numerous divergent field or force lines, each line intersecting the earth's surface at points on opposite sides of the Equator. The field lines which intersect the earth's surface near the poles have apexes which lie at the furthest points in the earth's magnetosphere while those closest to the Equator have apexes which reach only the lower portion of the magnetosphere.
At various altitudes above the earth's surface, e.g., in both the ionosphere and the magnetosphere, plasma is naturally present along these field lines. This plasma consists of equal numbers of positively and negatively charged particles (i.e., electrons and ions) which are guided by the field line. It is well established that a charged particle in a magnetic field gyrates about field lines, the center of gyration at any instance being called the "guiding center" of the particle. As the gyrating particle moves along a field line in a uniform field, it will follow a helical path about its guiding center, hence linear motion, and will remain on the field line. Electrons and ions both follow helical paths around a field line but rotate in opposite directions. The frequencies at which the electrons and ions rotate about the field line are called gyromagnetic frequencies or cyclotron frequencies because they are identical with the expression for the angular frequencies of gyratio!
n of particles in a cyclotron. The cyclotron frequency of ions in a given magnetic field is less than that of electrons, in inverse proportion to their masses.
If the particles which form the plasma along the earth's field lines continued to move with a constant pitch angle, often designated "alpha", they would soon impact on the earth's surface. Pitch angle alpha is defined as the angle between the direction of the earth's magnetic field and the velocity (V) of the particle. However, in converging force fields, the pitch angle does change in such a way as to allow the particle to turn around and avoid impact. Consider a particle moving along a field line down toward the earth. It moves into a region of increasing magnetic field strength and therefore sine alpha increases. But sine alpha can only increase to 1.0, at which point, the particle turns around and starts moving up along the field line, and alpha decreases. The point at which the particle turns around is called the mirror point, and there alpha equals ninety degrees. This process is repeated at the other end of the field line where the same magnetic field strength value B!
, namely Bm, exists. The particle again turns around and this is called the "conjugate point" of the original mirror point. The particle is therefore trapped and bounces between the two magnetic mirrors. The particle can continue oscillating in space in this manner for long periods of time. The actual place where a particle will mirror can be calculated from the following:
sin.sup.2 alpha.sub.o =B.sub.o /B.sub.m (1)
wherein:
alpha.sub.o =equatorial pitch angle of particle
B.sub.o =equatorial field strength on a particular field line
B.sub.m =field strength at the mirror point
Recent discoveries have established that there are substantial regions of naturally trapped particles in space which are commonly called "trapped radiation belts". These belts occur at altitudes greater than about 500 km and accordingly lie in the magnetosphere and mostly above the ionosphere.
The ionosphere, while it may overlap some of the trapped-particle belts, is a region in which hydrostatic forces govern its particle distribution in the gravitational field. Particle motion within the ionosphere is governed by both hydrodynamic and electrodynamic forces. While there are few trapped particles in the ionosphere, nevertheless, plasma is present along field lines in the ionosphere. The charged particles which form this plasma move between collisions with other particles along similar helical paths around the field lines and although a particular particle may diffuse downward into the earth's lower atmosphere or lose energy and diverge from its original field line due to collisions with other particles, these charged particles are normally replaced by other available charged particles or by particles that are ionized by collision with said particle. The electron density (N.sub.e) of the plasma will vary with the actual conditions and locations involved. Also, neu!
tral particles, ions, and electrons are present in proximity to the field lines.
The production of enhanced ionization will also alter the distribution of atomic and molecular constituents of the atmosphere, most notably through increased atomic nitrogen concentration. The upper atmosphere is normally rich in atomic oxygen (the dominant atmospheric constituent above 200 km altitude), but atomic nitrogen is normally relatively rare. This can be expected to manifest itself in increased airglow, among other effects.
As known in plasma physics, the characteristics of a plasma can be altered by adding energy to the charged particles or by ionizing or exciting additional particles to increase the density of the plasma. One way to do this is by heating the plasma which can be accomplished in different ways, e.g., ohmic, magnetic compression, shock waves, magnetic pumping, electron cyclotron resonance, and the like.
Since electron cyclotron resonance heating is involved in the present invention, a brief discussion of same is in order. Increasing the energy of electrons in a plasma by invoking electron cyclotron resonance heating, is based on a principle similar to that utilized to accelerate charged particles in a cyclotron. If a plasma is confined by a static axial magnetic field of strength B, the charged particles will gyrate about the lines of force with a frequency given, in hertz, as f.sub.g =1.54.times.10.sup.3 B/A, where: B=magnetic field strength in gauss, and A=mass number of the ion.
Suppose a time-varying field of this frequency is superimposed on the static field B confining the plasma, by passage of a radiofrequency current through a coil which is concentric with that producing the axial field, then in each half-cycle of their rotation about the field lines, the charged particles acquire energy from the oscillating electric field associated with the radio frequency. For example, if B is 10,000 gauss, the frequency of the field which is in resonance with protons in a plasma is 15.4 megahertz.
As applied to electrons, electron cyclotron resonance heating requires an oscillating field having a definite frequency determined by the strength of the confining field. The radio-frequency radiation produces time-varying fields (electric and magnetic), and the electric field accelerates the charged particle. The energized electrons share their energy with ions and neutrals by undergoing collisions with these particles, thereby effectively raising the temperature of the electrons, ions, and neutrals. The apportionment of energy among these species is determined by collision frequencies. For a more detailed understanding of the physics involved, see "Controlled Thermonuclear Reactions", Glasstone and Lovberg, D. Van Nostrand Company, Inc., Princeton, N.J., 1960 and "The Radiation Belt and Magnetosphere", Hess, Blaisdell Publishing Company, 1968, both of which are incorporated herein by reference.
Referring now to the drawings, the present invention provides a method and apparatus for altering at least one region of plasma which lies along a field line, particularly when it passes through the ionosphere and/or magnetosphere. FIG. 1 is a simplified illustration of the earth 10 and one of its dipole magnetic force or field lines 11. As will be understood, line 11 may be any one of the numerous naturally existing field lines and the actual geographical locations 13 and 14 of line 11 will be chosen based on a particular operation to be carried out. The actual locations at which field lines intersect the earth's surface is documented and is readily ascertainable by those skilled in the art.
Line 11 passes through region R which lies at an altitude above the earth's surface. A wide range of altitudes are useful given the power that can be employed by the practice of this invention. The electron cyclotron resonance heating effect can be made to act on electrons anywhere above the surface of the earth. These electrons may be already present in the atmosphere, ionosphere, and/or magnetosphere of the earth, or can be artificially generated by a variety of means such as x-ray beams, charged particle beams, lasers, the plasma sheath surrounding an object such as a missile or meteor, and the like. Further, artificial particles, e.g., electrons, ions, etc., can be injected directly into region R from an earth-launched rocket or orbiting satellite carrying, for example, a payload of radioactive beta-decay material; alpha emitters; an electron accelerator; and/or ionized gases such as hydrogen; see U.S. Pat. No. 4,042,196. The altitude can be greater than about 50 km if d!
esired, e.g., can be from about 50 km to about 800 km, and, accordingly may lie in either the ionosphere or the magnetosphere or both. As explained above, plasma will be present along line 11 within region R and is represented by the helical line 12. Plasma 12 is comprised of charged particles (i.e., electrons and ions) which rotate about opposing helical paths along line 11.
Antenna 15 is positioned as close as is practical to the location 14 where line 11 intersects the earth's surface. Antenna 15 may be of any known construction for high directionality, for example, a phased array, beam spread angle (.theta.) type. See "The MST Radar at Poker Flat, Alaska", Radio Science, Vol. 15, No. 2, Mar.-Apr. 1980, pps. 213-223, which is incorporated herein by reference. Antenna 15 is coupled to transmitter 16 which generates a beam of high frequency electromagnetic radiation at a wide range of discrete frequencies, e.g., from about 20 to about 1800 kilohertz (kHz).
Transmitter 16 is powered by power generator means 17 which is preferably comprised of one or more large, commercial electrical generators. Some embodiments of the present invention require large amounts of power, e.g., up to 10.sup.9 to 10.sup.11 watts, in continuous wave or pulsed power. Generation of the needed power is within the state of the art. Although the electrical generators necessary for the practice of the invention can be powered in any known manner, for example, by nuclear reactors, hydroelectric facilities, hydrocarbon fuels, and the like, this invention, because of its very large power requirement in certain applications, is particularly adapted for use with certain types of fuel sources which naturally occur at strategic geographical locations around the earth. For example, large reserves of hydrocarbons (oil and natural gas) exist in Alaska and Canada. In northern Alaska, particularly the North Slope region, large reserves are currently readily available. !
Alaska and northern Canada also are ideally located geographically as to magnetic latitudes. Alaska provides easy access to magnetic field lines that are especially suited to the practice of this invention, since many field lines which extend to desirable altitudes for this invention intersect the earth in Alaska. Thus, in Alaska, there is a unique combination of large, accessible fuel sources at desirable field line intersections. Further, a particularly desirable fuel source for the generation of very large amounts of electricity is present in Alaska in abundance, this source being natural gas. The presence of very large amounts of clean-burning natural gas in Alaskan latitudes, particularly on the North Slope, and the availability of magnetohydrodynamic (MHD), gas turbine, fuel cell, electrogasdynamic (EGD) electric generators which operate very efficiently with natural gas provide an ideal power source for the unprecedented power requirements of certain of the applicatio!
ns of this invention. For a more detailed discussion of the v!
arious means for generating electricity from hydrocarbon fuels, see "Electrical Aspects of Combustion", Lawton and Weinberg, Clarendon Press, 1969. For example, it is possible to generate the electricity directly at the high frequency needed to drive the antenna system. To do this, typically the velocity of flow of the combustion gases (v), past magnetic field perturbation of dimension d (in the case of MHD), follow the rule:
v=df
where f is the frequency at which electricity is generated. Thus, if v=1.78.times.10.sup.6 cm/sec and d=1 cm then electricity would be generated at a frequency of 1.78 mHz.
Put another way, in Alaska, the right type of fuel (natural gas) is naturally present in large amounts and at just the right magnetic latitudes for the most efficient practice of this invention, a truly unique combination of circumstances. Desirable magnetic latitudes for the practice of this invention interest the earth's surface both northerly and southerly of the equator, particularly desirable latitudes being those, both northerly and southerly, which correspond in magnitude with the magnetic latitudes that encompass Alaska.
Referring now to FIG. 2 a first ambodiment is illustrated where a selected region R.sub.1 of plasma 12 is altered by electron cyclotron resonance heating to accelerate the electrons of plasma 12, which are following helical paths along field line 11.
To accomplish this result, electromagnetic radiation is transmitted at the outset, essentially parallel to line 11 via antenna 15 as right hand circularly polarized radiation wave 20. Wave 20 has a frequency which will excite electron cyclotron resonance with plasma 12 at its initial or original altitude. This frequency will vary depending on the electron cyclotron resonance of region R.sub.1 which, in turn, can be determined from available data based on the altitudes of region R.sub.1, the particular field line 11 being used, the strength of the earth's magnetic field, etc. Frequencies of from about 20 to about 7200 kHz, preferably from about 20 to about 1800 kHz can be employed. Also, for any given application, there will be a threshhold (minimum power level) which is needed to produce the desired result. The minimum power level is a function of the level of plasma production and movement required, taking into consideration any loss processes that may be dominant in a part!
icular plasma or propagation path.
As electron cyclotron resonance is established in plasma 12, energy is transferred from the electromagnetic radiation 20 into plasma 12 to heat and accelerate the electrons therein and, subsequently, ions and neutral particles. As this process continues, neutral particles which are present within R.sub.1 are ionized and absorbed into plasma 12 and this increases the electron and ion densities of plasma 12. As the electron energy is raised to values of about 1 kilo electron volt (kev), the generated mirror force (explained below) will direct the excited plasma 12 upward along line 11 to form a plume R.sub.2 at an altitude higher than that of R.sub.1.
Plasma acceleration results from the force on an electron produced by a nonuniform static magnetic field (B). The force, called the mirror force, is given by
F=-.mu..gradient.B (2)
where .mu. is the electron magnetic moment and .gradient. B is the gradient of the magnetic field, .mu. being further defined as:
W.sub..perp. /B=mV.sub..perp..sup.2 /2B
where W.sub..perp. is the kinetic energy in the direction perpendicular to that of the magnetic field lines and B is the magnetic field strength at the line of force on which the guiding center of the particle is located. The force as represented by equation (2) is the force which is responsible for a particle obeying equation (1).
Since the magnetic field is divergent in region R.sub.1, it can be shown that the plasma will move upwardly from the heating region as shown in FIG. 1 and further it can be shown that
1/2M.sub.e V.sub.e.perp..sup.2 (x).apprxeq.1/2M.sub.e V.sub.e.perp..sup.2 (Y)+1/2M.sub.i V.sub.i.parallel..sup.2 (Y) (3)
where the left hand side is the initial electron transverse kinetic energy; the first term on the right is the transverse electron kinetic energy at some point (Y) in the expanded field region, while the final term is the ion kinetic energy parallel to B at point (Y). This last term is what constitutes the desired ion flow. It is produced by an electrostatic field set up by electrons which are accelerated according to Equation (2) in the divergent field region and pulls ions along with them. Equation (3) ignores electron kinetic energy parallel to B because V.sub.e.parallel. .apprxeq.V.sub.i.parallel., so the bulk of parallel kinetic energy resides in the ions because of their greater masses. For example, if an electromagnetic energy flux of from about 1 to about 10 watts per square centimeter is applied to region R, whose altitude is 115 km, a plasma having a density (N.sub.e) of 10.sup.12 per cubic centimeter will be generated and moved upward to region R.sub.2 which has a!
n altitude of about 1000 km. The movement of electrons in the plasma is due to the mirror force while the ions are moved by ambipolar diffusion (which results from the electrostatic field). This effectively "lifts" a layer of plasma 12 from the ionosphere and/or magnetosphere to a higher elevation R.sub.2. The total energy required to create a plasma with a base area of 3 square kilometers and a height of 1000 km is about 3.times.10.sup.13 joules.
FIG. 3 is an idealized representation of movement of plasma 12 upon excitation by electron cyclotron resonance within the earth's divergent force field. Electrons (e) are accelerated to velocities required to generate the necessary mirror force to cause their upward movement. At the same time neutral particles (n) which are present along line 11 in region R.sub.1 are ionized and become part of plasma 12. As electrons (e) move upward along line 11, they drag ions (i) and neutrals (n) with them but at an angle .theta. of about 13 degrees to field line 11. Also, any particulates that may be present in region R.sub.1, will be swept upwardly with the plasma. As the charged particles of plasma 12 move upward, other particles such as neutrals within or below R.sub.1, move in to replace the upwardly moving particles. These neutrals, under some conditions, can drag with them charged particles.
For example, as a plasma moves upward, other particles at the same altitude as the plasma move horizontally into the region to replace the rising plasma and to form new plasma. The kinetic energy developed by said other particles as they move horizontally is, for example, on the same order of magnitude as the total zonal kinetic energy of stratospheric winds known to exist.
Referring again to FIG. 2, plasma 12 in region R.sub.1 is moved upward along field line 11. The plasma 12 will then form a plume (cross-hatched area in FIG. 2) which will be relatively stable for prolonged periods of time. The exact period of time will vary widely and be determined by gravitational forces and a combination of radiative and diffusive loss terms. In the previous detailed example, the calculations were based on forming a plume by producing 0.sup.+ energies of 2 ev/particle. About 10 ev per particle would be required to expand plasma 12 to apex point C (FIG. 1). There at least some of the particles of plasma 12 will be trapped and will oscillate between mirror points along field line 11. This oscillation will then allow additional heating of the trapped plasma 12 by stochastic heating which is associated with trapped and oscillating particles. See "A New Mechanism for Accelerating Electrons in the Outer Ionosphere" by R. A. Helliwell and T. F. Bell, Journal of G!
eophysical Research, Vol. 65, No. 6, June, 1960. This is preferably carried out at an altitude of at least 500 km.
The plasma of the typical example might be employed to modify or disrupt microwave transmissions of satellites. If less than total black-out of transmission is desired (e.g., scrambling by phase shifting digital signals), the density of the plasma (N.sub.e) need only be at least about 10.sup.6 per cubic centimeter for a plasma orginating at an altitude of from about 250 to about 400 km and accordingly less energy (i.e., electromagnetic radiation), e.g., 10.sup.8 joules need be provided. Likewise, if the density N.sub.e is on the order of 10.sup.8, a properly positioned plume will provide a reflecting surface for VHF waves and can be used to enhance, interfere with, or otherwise modify communication transmissions. It can be seen from the foregoing that by appropriate application of various aspects of this invention at strategic locations and with adequate power sources, a means and method is provided to cause interference with or even total disruption of communications over a!
very large portion of the earth. This invention could be employed to disrupt not only land based communications, both civilian and military, but also airborne communications and sea communications (both surface and subsurface). This would have significant military implications, particularly as a barrier to or confusing factor for hostile missiles or airplanes. The belt or belts of enhanced ionization produced by the method and apparatus of this invention, particularly if set up over Northern Alaska and Canada, could be employed as an early warning device, as well as a communications disruption medium. Further, the simple ability to produce such a situation in a practical time period can by itself be a deterring force to hostile action. The ideal combination of suitable field lines intersecting the earth's surface at the point where substantial fuel sources are available for generation of very large quantitities of electromagnetic power, such as the North Slope of Alaska, pr!
ovides the wherewithal to accomplish the foregoing in a pract!
ical time period, e.g., strategic requirements could necessitate achieving the desired altered regions in time periods of two minutes or less and this is achievable with this invention, especially when the combination of natural gas and magnetohydrodynamic, gas turbine, fuel cell and/or EGD electric generators are employed at the point where the useful field lines intersect the earth's surface. One feature of this invention which satisfies a basic requirement of a weapon system, i.e., continuous checking of operability, is that small amounts of power can be generated for operability checking purposes. Further, in the exploitation of this invention, since the main electromagnetic beam which generates the enhanced ionized belt of this invention can be modulated itself and/or one or more additional electromagnetic radiation waves can be impinged on the ionized region formed by this invention as will be described in greater detail herein after with respect to FIG. 4, a substanti!
al amount of randomly modulated signals of very large power magnitude can be generated in a highly nonlinear mode. This can cause confusion of or interference with or even complete disruption of guidance systems employed by even the most sophisticated of airplanes and missiles. The ability to employ and transmit over very wide areas of the earth a plurality of electromagnetic waves of varying frequencies and to change same at will in a random manner, provides a unique ability to interfere with all modes of communications, land, sea, and/or air, at the same time. Because of the unique juxtaposition of usable fuel source at the point where desirable field lines intersect the earth's surface, such wide ranging and complete communication interference can be achieved in a resonably short period of time. Because of the mirroring phenomenon discussed hereinabove, it can also be prolonged for substantial time periods so that it would not be a mere transient effect that could simply !
be waited out by an opposing force. Thus, this invention prov!
ides the ability to put unprecedented amounts of power in the earth's atmosphere at strategic locations and to maintain the power injection level, particularly if random pulsing is employed, in a manner far more precise and better controlled than heretofore accomplished by the prior art, particularly by the detonation of nuclear devices of various yeilds at various altitudes. Where the prior art approaches yielded merely transitory effects, the unique combination of fuel and desirable field lines at the point where the fuel occurs allows the establishment of, compared to prior art approaches, precisely controlled and long-lasting effects which cannot, practically speaking, simply be waited out. Further, by knowing the frequencies of the various electromagnetic beams employed in the practice of this invention, it is possible not only to interfere with third party communications but to take advantage of one or more such beams to carry out a communications network even though t!
he rest of the world's communications are disrupted. Put another way, what is used to disrupt another's communications can be employed by one knowledgeable of this invention as a communications network at the same time. In addition, once one's own communication network is established, the far-reaching extent of the effects of this invention could be employed to pick up communication signals of other for intelligence purposes. Thus, it can be seen that the disrupting effects achievable by this invention can be employed to benefit by the party who is practicing this invention since knowledge of the various electromagnetic waves being employed and how they will vary in frequency and magnitude can be used to an advantage for positive communication and eavesdropping purposes at the same time. However, this invention is not limited to locations where the fuel source naturally exists or where desirable field lines naturally intersect the earth's surface. For example, fuel, particul!
arly hydrocarbon fuel, can be transported by pipeline and the!
like to the location where the invention is to be practiced.
FIG. 4 illustrates another embodiment wherein a selected region of plasma R.sub.3 which lies within the earth's ionosphere is altered to increase the density thereof whereby a relatively stable layer 30 of relatively dense plasma is maintained within region R.sub.3. Electromagnetic radiation is transmitted at the outset essentially parallel to field line 11 via antenna 15 as a right hand circularly polarized wave and at a frequency (e.g., 1.78 megahertz when the magnetic field at the desired altitude is 0.66 gauss) capable of exciting electron cyclotron resonance in plasma 12 at the particular altitude of plasma 12. This causes heating of the particles (electrons, ions, neutrals, and particulates) and ionization of the uncharged particles adjacent line 11, all of which are absorbed into plasma 12 to increase the density thereof. The power transmitted, e.g., 2.times.10.sup.6 watts for up to 2 minutes heating time, is less than that required to generate the mirror force F requ!
ired to move plasma 12 upward as in the previous embodiment.
While continuing to transmit electromagnetic radiation 20 from antenna 15, a second electromagnetic radiation beam 31, which is at a defined frequency different from the radiation from antenna 15, is transmitted from one or more second sources via antenna 32 into layer 30 and is absorbed into a portion of layer 30 (cross-hatched area in FIG. 4). The electromagnetic radiation wave from antenna 32 is amplitude modulated to match a known mode of oscillation f.sub.3 in layer 30. This creates a resonance in layer 30 which excites a new plasma wave 33 which also has a frequency of f.sub.3 and which then propogates through the ionosphere. Wave 33 can be used to improve or disrupt communications or both depending on what is desired in a particular application. Of course, more than one new wave 33 can be generated and the various new waves can be modulated at will and in a highly nonlinear fashion.
FIG. 5 shows apparatus useful in this invention, particularly when those applications of this invention are employed which require extremely large amounts of power. In FIG. 5 there is shown the earth's surface 40 with a well 41 extending downwardly thereinto until it penetrates hydrocarbon producing reservoir 42. Hydrocarbon reservoir 42 produces natural gas alone or in combination with crude oil. Hydrocarbons are produced from reservoir 42 through well 41 and wellhead 43 to a treating system 44 by way of pipe 45. In treater 44, desirable liquids such as crude oil and gas condensates are separated and recovered by way of pipe 46 while undesirable gases and liquids such as water, H.sub.2 S, and the like are separated by way of pipe 47. Desirable gases such as carbon dioxide are separated by way of pipe 48, and the remaining natural gas stream is removed from treater 44 by way of pipe 49 for storage in conventional tankage means (not shown) for future use and/or use in an elec!
trical generator such as a magnetohydrodynamic, gas turbine, fuel cell or EGD generator 50. Any desired number and combination of different types of electric generators can be employed in the practice of this invention. The natural gas is burned in generator 50 to produce substantial quantities of electricity which is then stored and/or passed by way of wire 51 to a transmitter 52 which generates the electromagnetic radiation to be used in the method of this invention. The electromagnetic radiation is then passed by way of wire 53 to antenna 54 which is located at or near the end of field line 11. Antenna 54 sends circularly polarized radiation wave 20 upwards along field line 11 to carry out the various methods of this invention as described hereinabove.
Of course, the fuel source need not be used in its naturally-occurring state but could first be converted to another second energy source form such as hydrogen, hydrazine and the like, and electricity then generated from said second energy source form.
It can be seen from the foregoing that when desirable field line 11 intersects earth's surface 40 at or near a large naturally-occurring hydrocarbon source 42, exceedingly large amounts of power can be very efficiently produced and transmitted in the direction of field lines. This is particularly so when the fuel source is natural gas and magnetohydrodynamic generators are employed. Further, this can all be accomplished in a relatively small physical area when there is the unique coincidence of fuel source 42 and desirable field line 11. Of course, only one set of equipment is shown in FIG. 5 for sake of simplicity. For a large hydrocarbon reservoir 42, a plurality of wells 41 can be employed to feed one or more storage means and/or treaters and as large a number of generators 55 as needed to power one or more transmitters 52 and one or more antennas 54. Since all of the apparatus 44 through 54 can be employed and used essentially at the sight where naturally-occurring fuel !
source 42 is located, all the necessary electromagnetic radiation 20 is generated essentially at the same location as fuel source 42. This provides for a maximum amount of usable electromagnetic radiation 20 since there are no significant storage or transportation losses to be incurred. In other words, the apparatus is brought to the sight of the fuel source where desirable field line 11 intersects the earth's surface 40 on or near the geographical location of fuel source 42, fuel source 42 being at a desirable magnetic latitude for the practice of this invention, for example, Alaska.
The generation of electricity by motion of a conducting fluid through a magnetic field, i.e., magnetohydrodynamics (MHD), provides a method of electric power generation without moving mechanical parts and when the conducting fluid is a plasma formed by combustion of a fuel such as natural gas, an idealized combination of apparatus is realized since the very clean-burning natural gas forms the conducting plasma in an efficient manner and the thus formed plasma, when passed through a magnetic field, generates electricity in a very efficient manner. Thus, the use of fuel source 42 to generate a plasma by combustion thereof for the generation of electricity essentially at the site of occurrence of the fuel source is unique and ideal when high power levels are required and desirable field lines 11 intersect the earth's surface 40 at or near the site of fuel source 42. A particular advantage for MHD generators is that they can be made to generate large amounts of power with a smal!
l volume, light weight device. For example, a 1000 megawatt MHD generator can be construed using superconducting magnets to weigh roughly 42,000 pounds and can be readily air lifted.
This invention has a phenomenal variety of possible ramifications and potential future developments. As alluded to earlier, missile or aircraft destruction, deflection, or confusion could result, particularly when relativistic particles are employed. Also, large regions of the atmosphere could be lifted to an unexpectedly high altitude so that missiles encounter unexpected and unplanned drag forces with resultant destruction or deflection of same. Weather modification is possible by, for example, altering upper atmosphere wind patterns or altering solar absorption patterns by constructing one or more plumes of atmospheric particles which will act as a lens or focusing device. Also as alluded to earlier, molecular modifications of the atmosphere can take place so that positive environmental effects can be achieved. Besides actually changing the molecular composition of an atmospheric region, a particular molecule or molecules can be chosen for increased presence. For example,!
ozone, nitrogen, etc. concentrations in the atmosphere could be artificially increased. Similarly, environmental enhancement could be achieved by causing the breakup of various chemical entities such as carbon dioxide, carbon monoxide, nitrous oxides, and the like. Transportation of entities can also be realized when advantage is taken of the drag effects caused by regions of the atmosphere moving up along diverging field lines. Small micron sized particles can be then transported, and, under certain circumstances and with the availability of sufficient energy, larger particles or objects could be similarly affected. Particles with desired characteristics such as tackiness, reflectivity, absorptivity, etc., can be transported for specific purposes or effects. For example, a plume of tacky particles could be established to increase the drag on a missile or satellite passing therethrough. Even plumes of plasma having substantially less charged particle density than described !
above will produce drag effects on missiles which will affect!
a lightweight (dummy) missile in a manner substantially different than a heavy (live) missile and this affect can be used to distinguish between the two types of missiles. A moving plume could also serve as a means for supplying a space station or for focusing vast amount of sunlight on selected portions of the earth. Surveys of global scope could also be realized because the earth's natural magnetic field could be significantly altered in a controlled manner by plasma beta effects resulting in, for example, improved magnetotelluric surveys. Electromagnetic pulse defenses are also possible. The earth's magnetic field could be decreased or disrupted at appropriate altitudes to modify or eliminate the magnetic field in high Compton electron generation (e.g., from high altitude nuclear bursts) regions. High intensity, well controlled electrical fields can be provided in selected locations for various purposes. For example, the plasma sheath surrounding a missile or satellite c!
ould be used as a trigger for activating such a high intensity field to destroy the missile or satellite. Further, irregularities can be created in the ionosphere which will interfere with the normal operation of various types of radar, e.g., synthetic aperture radar. The present invention can also be used to create artificial belts of trapped particles which in turn can be studied to determine the stability of such parties. Still further, plumes in accordance with the present invention can be formed to simulate and/or perform the same functions as performed by the detonation of a "heave" type nuclear device without actually having to detonate such a device. Thus it can be seen that the ramifications are numerous, far-reaching, and exceedingly varied in usefulness.
* * * * *
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United States Patent 4,999,637
Bass March 12, 1991
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Creation of artificial ionization clouds above the earth
Abstract
A method for forming a cloud of artificial ionization above the earth by initially heating the resident plasma at a desired altitude with electromagnetic radiation having a frequency approximately the same as that of the ambient plasma. As the plasma frequency increases due to heating, the radiation frequency is also increased until the final maintenance frequency is attained.
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Inventors: Bass; Ronald M. (Houston, TX)
Assignee: APTI, Inc. (Washington, DC)
Appl. No.: 049881
Filed: May 14, 1987
Current U.S. Class: 342/367; 342/5
Intern'l Class: H04B 007/00
Field of Search: 361/231 342/352,5,367 376/123,124
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References Cited [Referenced By]
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U.S. Patent Documents
3133250 May., 1964 Molmud 342/352.
3174150 Jan., 1965 Sferrazza et al. 342/352.
3189901 Jun., 1965 Cutolo 342/350.
3300721 Jan., 1967 Seaton 342/352.
3445844 May., 1969 Grossi et al. 342/367.
3518670 Jun., 1970 Miller 342/5.
3882393 May., 1975 Epstein 455/59.
4035726 Jul., 1977 Brice et al. 342/352.
4686605 Aug., 1987 Eastlund 361/231.
4712155 Dec., 1987 Eastlund et al. 361/231.
Other References
Radio Science, vol. 15, No. 2, pp. 213-223, (4/80), "MST Radar at Poker Flat, Alaska", Balsley et al.
Primary Examiner: Cangialosi; Salvatore
Attorney, Agent or Firm: Faulconer; Drude
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Claims
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What is claimed is:
1. A method of forming a cloud of artificial ionization at an altitude above the earth, said method comprising:
initiating heating of the resident plasma at said altitude by transmitting electromagnetic radiation from the earth to said altitude at an initial frequency which is approximately the same as the original frequency of said resident plasma; and
increasing said frequency of said electromagnetic radiation as said frequency of said resident plasma increases, until a final maintenance frequency is attained, said maintenance frequency being t or above the plasma frequency necessary to provide a plasma having an electron density capable of reflecting communication or like signals which come into contact with said plasma.
2. The method of claim 1 including:
defocusing said electromagnetic radiation so only the center area of said cloud is initially heated; and
contracting the focus of said electromagnetic radiation as the frequency of said radiation is adjusted until the entire area of said cloud is heated.
3. The method of claim 1 wherein said electromagnetic radiation is transmitted by a single antenna system.
4. The method of claim 1 wherein said electromagnetic radiation is transmitted by two antenna systems, each spaced from the other, and inclined whereby the beams of said electromagnetic radiation transmitted from said systems will intersect each other at said altitude.
5. A variable frequency heating method for forming a cloud of artificial ionization at an altitude above the earth, said method comprising:
transmitting electromagnetic radiation form the earth to said altitude at an initial frequency which is approximately the same as the original frequency of the plasma naturally present at said altitude;
focusing said electromagnetic radiation to heat said plasma to thereby accelerate the free electrons therein thereby increasing the frequency of said plasma;
monitoring the frequency of said plasma as it increases;
increasing the frequency of said electromagnetic radiation as said frequency of said plasma increases;
continuing to increase said frequency of said electromagnetic radiation until a final desired maintenance frequency is attained; said final desired frequency being at or above the plasma frequency necessary to provide a plasma having an electron density capable of reflecting communication signals or the like which come into contact with said plasma;
and continuing to transmit said electromagnetic radiation at said final frequency to maintain the integrity of said cloud.
6. The method of claim 5 wherein said final frequency is greater than the frequency of any communication and/or radar signals expected to be reflected by said cloud.
7. The method of claim 6 wherein said electromagnetic radiation is initially focused whereby only the center area of said plasma is initially heated.
8. The method of claim 7 including:
contracting the focus of said electromagnetic radiation as the said frequency of said radiation is increased whereby the entire area of said cloud is heated.
9. The method of claim 8 wherein said frequency of said electromagnetic radiation is increased to approximately match said increasing frequency of said plasma.
10. The method of claim 9 wherein said electromagnetic radiation is transmitted by a single antenna system.
11. The method of claim 9 wherein said electromagnetic radiation is transmitted by two antenna systems, each spaced from the other, and inclined whereby the beams of said electromagnetic radiation transmitted from said systems will intersect each other at said altitude.
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Description
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DESCRIPTION
1. Technical Field
The present invention relates to a method for establishing a patch or cloud of artificial ionization above the earth and more particularly, relates to a method of forming a cloud of artificial ionization by heating naturally occurring plasma with electromagnetic energy which is transmitted from the Earth's surface at a variable, increasing frequency.
2. Background Act
Certain communication and radar systems operate by "bouncing" transmitted and/or reflected signals off of naturally-occurring layers of ionization in the ionosphere. One known system using this technique is "over-the-horizon" (OTH) radar. By bouncing or reflecting the signals off an ionized layer, the signals can actually travel "over-the-horizon", thereby substantially increasing the range of the system.
However, while present OTH systems are capable of detecting objects at long range (e.g. strategic threats), they are not well suited for detecting "close-in" objects (e.g. missiles at 1000 kilometers or less). One problem lies in the fact that as the beam angle of the radar is increased from the horizontal, the frequency of the beam must be lowered in order to achieve refraction at a more nearly normal incidence. As this frequency is lowered, the antenna system gain is reduced and the radar cross section decreases for small close-in object. These effects act to set a minimum range for the OTH system.
Another major problem with present OTH systems is related to the low radar cross section of small targets at typical OTH operating frequencies. These objects having small cross-sections produce a weak return signal even when the object is within the range of the OTH radar since the OTH system is normally designed for objects having much larger cross-sections, e.g. large aircraft.
A still further problem encountered by present OTH radar is directly related to the unstable conditions in the ionosphere which widely vary depending on seasonal, diurnal, and/or sunspot cycles. Accordingly, the operating frequency of present OTH radar systems has to be constantly adjusted to allow for the varying ionospheric conditions which may vary so much at times that the OTH system is rendered inoperable.
Several techniques have been proposed to overcome some of the shortfalls of present OTH radar systems. One known technique is disclosed in U.S. Pat. No. 3,445,844 wherein a cloud of artificial ionization is formed above the earth to serve as a layer for redirecting communication signals. The cloud is formed by "breakdown", i.e. creation of a high level flux of free electrons (i.e. plasma) at a desired altitude by focusing electromagnetic energy thereon to heat a localized region or area. The electromagnetic energy heats and accelerate the electrons in the resident plasma to a degree such that their kinetic energy reaches the level required for the occurrence of ionizing collisions. Scattering from a cloud so formed takes place due to the discontinuity between this zone of enhanced ionization and the surrounding medium.
A cloud formed in accordance with the method disclosed in U.S. Pat. No. 3,445,844 will provide a good reflection layer for OTH radar and like systems. However, when a cloud is formed by breakdown as in the mentioned patent, the plasma frequency of the cloud quickly adjusts to the hating frequency and breakdown is initiated over the entire area of the cloud. By initiating and forming the cloud with radiation having the same high frequency as that required for continued maintenance of the cloud once formed, a substantial amount of power is required, much of which is reflected or passes through the cloud while it is being formed and, accordingly, is wasted.
BRIEF DESCRIPTION OF THE DRAWINGS
The actual construction, operation, and apparent advantages of this invention will be better understood by referring to the drawings in which like numerals identify like parts and in which:
FIG. 1 is a simplified schematical view of a system for forming a cloud of artificial ionization above the earth for bouncing signals over-the-horizon in accordance with the present invention; and
FIG. 2 is a schematic illustration of a cross-beam radiation transmission system for forming a cloud of artificial ionization in accordance with the present invention.
DISCLOSURE OF THE INVENTION
The present invention provides a method for forming a patch or cloud of artificial ionization at an altitude above the earth wherein no substantial amounts of power are wasted in forming and maintaining the cloud.
More specifically, the present invention provides a method wherein variable frequency heating is used to form a cloud of artificial ionization. This is accomplished by initially heating the resident plasma at the selected altitude by transmitting electromagnetic radiation from the earth at an initial frequency which is approximately the same frequency as the ambient plasma frequency. This radiation, being of the same frequency as the plasma, will be efficiently absorbed with relatively little being reflected from or passed through the ambient plasma. The radiation heats the plasma and accelerates the free electrons in the plasma thereby increasing the plasma frequency.
The frequency of the plasma is monitored by radar or the like and, as it increases, the frequency of the radiation being transmitted also increases, preferably in a manner where the radiatio |
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United States Patent 5,068,669
Koert , et al. November 26, 1991
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Power beaming system
Abstract
A system and method for power beaming energy from a source at high frequencies and rectifying such energy to provide a source of DC energy is disclosed. The system operates at a frequency of at least 10 GHz and incorporates a rectenna array having a plurality of rectenna structures that utilize circuit elements formed with microstrip circuit techniques.
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Inventors: Koert; Peter (Washington, DC); Cha; James T. (Fairfax, VA)
Assignee: APTI, Inc. (Washington, DC)
Appl. No.: 239284
Filed: September 1, 1988
Current U.S. Class: 343/700MS; 343/DIG2
Intern'l Class: H01Q 001/380; H01Q 013/080; H01Q 001/280
Field of Search: 343/700 MS,705,708,846,DIG. 2 307/151 361/395
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References Cited [Referenced By]
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U.S. Patent Documents
3434678 Mar., 1969 Brown et al. 244/1.
3542316 Nov., 1970 Hart 244/17.
3989994 Nov., 1976 Brown 343/771.
4079268 Mar., 1978 Fletcher et al. 343/700.
4360741 Nov., 1982 Fitzsimmons et al. 307/151.
4697761 Oct., 1987 Long 244/62.
4837576 Jun., 1989 Schwarz 342/77.
Other References
Brown, W. C., Update on the Solar Power Satellite Xmitter Design, Space Power, vol. 6, pp. 123-135, 1986.
Buechler et al., Silicon High Resistivity-Substrate Millimeter Wave Technology, IEEE Transactions on Microwave Theory and Technologies, vol. MTT-34, No. 12, Dec. 1986.
"Synchotron Radiation Conversion by Rectennas for ARIS-II", by John Santarius, dated Aug. 22, 1989.
"Millimeter-Wave/Infrared Rectenna Development at Georgia Tech", by Mark A. Gouker, Power Beaming Workshop, Apr. 1988.
William C. Brown, "Rectenna Technology Program: Ultra Light 2.45 GHz Rectenna and 20 GHz Rectenna", Raytheon Company, NASA Report No. CR179558, Mar. 11, 1987.
"The History of Power Transmission by Radio Waves", William C. Brown, IEEE Transactions on Microwave Theory and Techniques, vol. MTT-32, No. 9, Sep. 1984.
"A Microwave Powered High Altitude Platform", Schlesak et al., IEEE MTT-S Digest, pp. 283-286, 1988.
"Introduction to Gyro Devices", Varian, Publication No. 4762 11/84.
"Very High Power mm-Wave Components in Oversized Waveguides", by Thumm et al., Microwave Journal, Nov. 1986.
Primary Examiner: Hille; Rolf
Assistant Examiner: Brown; Peter Toby
Attorney, Agent or Firm: Foley & Lardner
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Claims
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What is claimed is:
1. A power beaming system comprising:
a. a power transmission source capable of generating electromagnetic radiation having a frequency of at least 10 Gigahertz;
b. a transmission antenna;
c. a guide unit that guides said electromagnetic radiation generated by said power transmission source to said transmission antenna;
d. a rectenna array located at a position remote from said antenna structure, said rectenna array comprising a plurality of multi-layer rectenna structures, each multi-layer rectenna structure including a first substrate layer having at least one receiving antenna provided thereon, a ground plane layer and a second substrate layer having circuit elements provided thereon, wherein said rectenna array includes a power combining network, said power combining network including a plurality of first current summing elements, each current summing element comprising a plurality of said multi-layer rectenna structures electrically connected in parallel, and at least one voltage summing element comprising a plurality of said first current summing elements electrically connected in series.
2. A power beaming system as set forth in claim 1, further comprising:
i. a movable pedestal supporting said transmission antenna;
ii. a direction beacon that generates a tracking signal indicative of the location of said rectenna array;
iii. a pedestal control unit coupled to said pedestal; and
iv. a receiver unit electrically coupled to the pedestal control unit that receives the tracking signal from the direction beacon and provides the tracking signal to the pedestal control unit.
3. A power beaming system as claimed in claim 1, wherein said power transmission source generates said electromagnetic radiation at a frequency of at least 18 GHz.
4. A power beaming system as claimed in claim 1, wherein said power transmission source generates electromagnetic radiation at frequency of about 28-44 GHz.
5. A power beaming system as claimed in claim 1, wherein said power transmission source generates electromagnetic radiation at a frequency of about 35 GHz.
6. A power beaming system as claimed in claim 1, wherein said power transmission source is a gyrotron.
7. A power beaming system as claimed in claim 6, wherein said guide unit provides mode conversion of the electromagnetic radiation generated by said gyrotron.
8. A power beaming system as claimed in claim 7, wherein said guide unit comprises a waveguide assembly.
9. A power beaming system as claimed in claim 8, wherein said guide assembly comprises a beam waveguide.
10. A power beaming system as claimed in claim 1, wherein said receiving antenna of said multilayer rectenna structure receives said electromagnetic radiation independently of its polarization.
11. A power beaming system as claimed in claim 10, wherein said receiving antenna comprises a patch antenna.
12. A power beaming system as claimed in claim 1, wherein said circuit elements comprise an impedance matching circuit, a diode and an output filter.
13. A power beaming system as claimed in claim 1, wherein said power combining network further comprises at least one second current summing element comprising a plurality of said voltage summing elements electrically connected in parallel.
14. A multi-layer rectenna structure comprising:
a. a first substrate having at least one receiving antenna provided thereon;
b. a second substrate having circuit elements provided thereon; and
c. a ground plane located between said first and second substrate; and
d. wherein said circuit elements comprise an impedance matching filter coupled to said receiving antenna via a coupling capacitance, a diode electrically coupled to said matching filter, and an output filter electrically coupled to said diode.
15. A multi-layer rectenna structure as claimed in claim 14, wherein said impedance matching filter and said output filter are formed using microstrip circuit techniques.
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Description
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BACKGROUND OF THE INVENTION
The present invention relates in general to the transfer of energy by means of electromagnetic waves to power a remote device. More specifically, the present invention relates to a system for "power beaming" energy from a source at high frequencies and rectifying such energy to provide a source of DC energy to a remote device.
Attempts have been made for many years to develop a system for beaming energy from a source to power a remote device with a high degree of efficiency (for a general discussion see "The History of Power Transmission by Radio Waves" by William C. Brown, IEEE Transactions on Microwave Theory and Techniques, Vol. MTT-32, No. 9, September 1984). In particular, the concept of powering a satellite or free flying aircraft by power beaming has received a great deal of attention. The advantages of such a system are readily apparent, for example, an aircraft could be maintained on station indefinitely to act as a low cost communications or reconnaissance platform. Early concepts included the conversion of microwave energy into thermal energy to power a helicopter type platform as illustrated in U.S. Pat. 4,542,316 issued to Hart. A more practical approach, however, has focused on converting the microwave energy into DC energy to directly power the platform.
The practical conversion of microwave energy to DC energy for power beaming purposes has been based on the use of rectennas to receive and rectify the microwave energy. Generally, rectennas are limited in their power-handling capabilities, but can be a highly efficient means of converting microwave energy into DC energy for power beaming purposes when employed in large numbers in an array structure. U.S. Pat. 3,434,678 issued to Brown et al. illustrates the use of a rectenna array to power a helicopter platform by power beaming.
More recently, a scale model of a long endurance high altitude platform powered by microwave energy known as SHARP (Stationary High Altitude Relay Platform) has been successfully demonstrated. See "A Microwave Powered High Altitude Platform" by Schlesak et al., 1988 IEEE MTT-S Digest, pp. 283-286. The SHARP concept calls for an array of ground antennas which must be focused on the aircraft. The underside of the aircraft would be coated with a thin-film array of thousands of half-wave dipole rectennas to convert the received microwave energy into DC energy which would be used to power the aircraft's electrical motor. The scale model of the SHARP aircraft was powered by a microwave beam formed from the outputs of two 5 kW continuous-wave magnetrons, which were combined and supplied to a 4.5 meter diameter parabolic antenna to transmit 10 kilowatts of energy at a frequency of 2.45 GHz. Dual polarization rectennas formed of two orthogonal linearly-polarized rectenna arrays were !
provided on the model aircraft to convert the microwave energy to DC power.
Efforts at power beaming to date, like SHARP discussed above, have focused primarily on using S-band transmission sources due to their ready availability and to reduce power losses due to atmospheric attenuation. S-band power beaming, however, is limited in the amount of power that can be delivered in a practical system. In order to generate sufficient power densities, a large array of ground antennas must be employed which complicates the problem of concentrating the transmitted energy on the aircraft. One could reduce the number of ground antennas employed in the array, but the size of the antennas would increase significantly making them as difficult to track as the array while greatly increasing their expense. In addition, S-band power beaming requires a large amount of surface area for the rectenna array on the aircraft to generate significant power quantities. For example, the SHARP system discussed above would need an array of 100 m.sup.2 of rectenna surface to genera!
te only 35 kW of DC power, 25 kW of which is required to power the propulsion system, while requiring a transmitter having a diameter of 85 meters with an output of 500 kw.
SUMMARY OF THE INVENTION
The present invention departs from the prior art by providing a power beaming system that operates at a much higher frequency, on the order of tens of GHz, to thereby provide a system having a power density an order in magnitude greater than conventional power beaming systems while at the same time having the advantage of a smaller transmission source and rectenna array.
More specifically, the present invention provides a power beaming system including a power transmission source capable of generating electromagnetic radiation having a frequency of at least 10 Gigahertz, a transmission antenna mounted on a movable pedestal, a guide unit that guides the electromagnetic radiation generated by the power transmission source to the transmission antenna, a rectenna array located at a position remote from the antenna structure, wherein the rectenna array includes a plurality of multi-layer rectenna structures. Each multi-layer rectenna structure includes a first substrate layer having at least one receiving antenna provided thereon, a ground plane layer and a second substrate layer having circuit elements provided thereon.
BRIEF DESCRIPTION OF THE DRAWINGS
A preferred exemplary embodiment will hereinafter be described in conjunction with the appended drawings wherein like designations denote like elements, and wherein:
FIG. 1 is an overall system diagram of a power beaming system according to the present invention;
FIG. 2 is a graph illustrating atmospheric attenuation of electromagnetic waves at various frequencies;
FIG. 3a illustrates a planar rectenna structure that may be incorporated in the system illustrated in FIG. 1;
FIG. 3b is a circuit diagram of the planar rectenna array shown in FIG. 3a;
FIG. 4a illustrates a second planar rectenna structure that may be incorporated in the system illustrated in FIG. 1;
FIG. 4b is a circuit diagram of the planar rectenna illustrated in FIG. 4a;
FIGS. 5a and 5b illustrate top and bottom surfaces, respectively, of a multi-layer rectenna structure that may be incorporated in the system illustrated in FIG. 1; and
FIGS. 6 illustrates various components of a power combining network;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, a power beaming system according to the present invention is illustrated having a power transmission source 10 operating at a frequency of at least 10 GHz, and more preferably at least 18 GhZ, that feeds energy to an antenna 14 via a guide unit 12. The antenna 14 is mounted to a movable precision pedestal 8 that is controlled by a pedestal control unit 24. The energy generated by the power transmission source 10 is focused into a beam by the antenna 14 to illuminate a preferable circular rectenna array 16 affixed to the bottom of an electrically powered aircraft 18. The rectenna array 16 converts the energy received from the antenna 14 to DC energy which is used to directly drive the electrical motor of the aircraft 18. The aircraft 18 in a preferred embodiment operates at an altitude of 21 kilometers.
In order to aid in tracking the antenna 14 to the movements of the aircraft 18, a directional beacon 20 is fixed to the center of the rectenna array 16. The directional beacon 20, preferably operating in the X-band frequency range, emits a tracking signal that is received by a receiver 22 located on the antenna 14. The output signal from the receiver 22 is used by a pedestal control unit 24 to control the tracking movements of the antenna 14 and insure that the energy beam generated by the system is centered on the rectenna array 16.
As previously mentioned, one of the reasons conventional systems have been limited to S-band power beaming is to reduce power losses due to atmospheric attenuation of the transmitted beam. Generally, attenuation increases as operating frequency increases as illustrated by the chart shown in FIG. 2 (see "Radar Handbook" by M.I. Skolnik, McGraw-Hill Book Company, N.Y. 1970, p. 24-26). At around 35 GHz., however, atmospheric attenuation drops off. Thus, a power beaming system operating in the range of about 28-44 GHz and preferably around 35 GHz, provides the advantages associated with operating at higher transmission frequencies, such as the reduction in size of the ground antenna and the rectenna array while operating at higher power densities, with approximately the same amount of attenuation experienced at lower frequencies.
In order to generate sufficient power densities at the desired frequency, one or more gyrotrons are preferably used for the power transmission source 10. The term "gyrotron" will be used throughout this specification to generically describe microwave oscillators based on the interaction of electrons orbiting in a DC magnetic field under the conditions of cyclotron resonance where the magnitude of the DC magnetic field and the microwave frequency are specifically related. Typically gyrotrons include single-cavity oscillators wherein the entire interaction takes place in a single microwave cavity, but it will be understood that the same basic interaction can be used with varying devices, such as amplifiers using several resonant cavities, which may sometimes be referred to as gyroklystrons, gyro TWTs or even cyclotron resonance masers, and that the term gyrotron is intended to cover all such devices. A more detailed explanation of gyrotrons is provided in the paper "Introducti!
on to Gyro Devices", VARIAN publication number 4762 11/84, incorporated herein by reference. Gyrotrons producing power outputs between 200-300 kW at frequencies of 28 Ghz to 60 GHz are presently in use, and the outputs of one or more gyrotrons can be combined to obtain desired power output levels for the power transmission source 10.
Gyrotrons generally produce TE.sub.On modes which produce a hollow conical radiation pattern with zero power along the waveguide axis. When using a gyrotron for the power transmission source 10, however, it is desirable to perform a mode conversion operation in order to generate a narrow beam with a well-defined polarization. Accordingly, the guide unit 12 is constructed to perform the desired mode conversion. Mode converter assemblies for use in the guide unit 12 may be constructed out of waveguide assemblies as illustrated in the paper entitled, "Very High Power mm-Wave Components in Oversized Waveguides" by Thumm et al., Microwave Journal, November 1986 incorporated herein by reference, to produce a beam having the desired characteristics. Alternatively, beam waveguides could be employed for the guide unit 12 as described in the article entitled "Some Aspects of Beam Waveguide Design" by Chan et al., IEEE Proceedings, Vol. 129 Pt H No. 4, August 1982, incorporated herein !
by reference.
Referring now to FIG. 3a, a planar rectenna 26 that may be employed in the rectenna array of the present system is shown having a patch antenna 30 which acts as a 1/2 wave resonator, an impedance matching filter 32, coupled to the patch antenna 30 by a blocking capacitance 31, for matching the impedance of the patch antenna 30 to a diode 34 (for example, ALPHA DMK6606), and an output filter 36.
The impedance matching filter 32 and output filter 36 of the planar rectenna 26 are formed using microstrip circuitry techniques on a dielectric substrate 38 (for example RT-DUROID manufactured by Rogers Corporation, dielectric constant 2.2) of the planar rectenna 26. Microstrip circuitry provides a simple and economical method of providing the circuit elements of the impedance matching filter 32 and output filter 36 in a compact structure, and permits the diode 34 to be located as close as possible to the patch antenna thereby avoiding losses due to lengthy interconnect lines. For example, the components of the impedance matching circuit 32 and the output filter 36 are formed by conventional copper etching techniques on a top surface of the dielectric substrate 38. A ground pad 40 is also provided to provide electrical connection via plated through holes to a ground plane (not shown) provided beneath the dielectric substrate 38.
The patch antenna 30 provides the advantage of dual polarization in a very simple structure without necessitating the overlapping of two linearly-polarized antenna layers. Other antenna structures may be employed; however, an antenna which is independent of the polarization of the incoming electromagnetic radiation is preferred.
A circuit diagram of the planar rectenna 26 is provided in FIG. 3b. Configurations and circuit arrangements other than those illustrated in FIG. 3a and 3b are of course possible. For example, a second planar rectenna structure is illustrated in FIG. 4a which does not utilize an impedance matching filter. The circuit diagram for this planar rectenna structure is shown in FIG. 4b. The impedance matching filter is desirable, however, to optimize the output of the rectenna.
While the above described rectenna structure has been demonstrated to operate effectively in the frequency range of interest, it has a disadvantage in that the impedance matching and output filters take up a large percentage of the surface area of the substrate which limits the power conversion efficiency of the rectenna array. In other words, the rectenna array provides maximum efficiency when the maximum number of antennas can be provided on the surface area of the array. This problem can be addressed by providing a multi-layer rectenna structure, as opposed to the planar rectenna illustrated in FIG. 3, in which the antenna is located on the surface of the substrate and the circuit elements, i.e., the impedance matching and output filters and the diode, are located in a separate layer beneath the antenna to provide a compact structure.
Referring now to FIG. 5a, a top surface 41 of a rectenna array 43 incorporating multi-layer rectennas is shown having a first substrate 42 on which a patch antenna 30' of each multi-layer rectenna is provided, a copper ground plane 44, and a second substrate 46 on which the circuit elements, i.e., the impedance matching filter 32', diode 34' and output filter 36', are provided as shown in FIG. 5b. The patch antennas 30' are coupled to the impedance matching filter 32' on the bottom surface 45 of the rectenna array 43 via plated-through holes 47. Thus, the patch antennas 30' may be readily spaced in the rectenna array (in this case 1/2 wavelength center to center) to provide maximum power conversion efficiency while maintaining a rectenna structure that may be easily fabricated using multi-layer circuit board fabrication techniques. It will be readily understood that in an array structure one output filter may be provided for a plurality of rectennas instead of providing each!
rectenna with its own output filter, and that the circuit elements may be provided on the inside surface of the substrate 46 if an insulating layer is positioned between the circuit elements and the ground plane 44.
It is of course necessary to combine the outputs from each of the individual rectennas in the array 43 to provide useful voltage and current levels. FIGS. 6 illustrates a power combining network which can be used to match the voltage and current output of the rectenna array to any desired load. In addition, the power combining network prevents the failure of one or more rectennas from seriously effecting the output of the entire array by providing a plurality of current and voltage summing elements.
As shown in FIG. 6, a current summing element 50 is formed by combining the output of several individual rectennas 49 in parallel. The resistance R.sub.t represents the resistance associated with the interconnect lines between the individual rectennas. Discrete resistors R.sub.sl, having a value much greater than R.sub.t, couple the rectennas to a diode D.sub.dc. The current summing elements may then be combined in series to form a voltage summing element 52. Individual voltage summing elements 52 can then be combined to form additional current summing elements 54. Switching elements 56 are also provided so that the various current and voltage summing elements can be combined in any desired pattern to match the voltage and current requirements of the load.
It will be readily understood that variations and modifications may be made within the spirit and scope of the invention as expressed in the appended claims, and that the invention is not limited to the specific forms illustrated above. For example, many different circuit configurations for the rectenna structures are possible, along with different combinations of summing elements in the power combining network. In addition, a single output filter may be provided for a plurality of rectenna structures in an array, rather than providing an output filter for each rectenna structure.
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United States Patent 5,041,834
Koert August 20, 1991
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Artificial ionospheric mirror composed of a plasma layer which can be tilted
Abstract
This invention relates to generation of a Artificial Ionospheric Mirror (AIM), or a plasma layer in the atmosphere. The AIM is used like the ionosphere to reflect RF energy over great distances. A tiltable AIM is created by a heater antenna controlled in phase and frequency. The heater antenna phase shift scans a beam to paint a plasma layer. Frequency is changed to refocus at continually higher altitudes to tilt the plasma layer.
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Inventors: Koert; Peter (Washington, DC)
Assignee: APTI, Inc. (Washington, DC)
Appl. No.: 524435
Filed: May 17, 1990
Current U.S. Class: 342/367; 342/372
Intern'l Class: H04B 007/00; H01Q 003/22
Field of Search: 342/367,353,371,372 455/64
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References Cited [Referenced By]
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U.S. Patent Documents
3445844 May., 1969 Grossi et al. 342/367.
4253190 Feb., 1981 Csonka 455/12.
4686605 Aug., 1987 Eastlund 361/231.
4712155 Dec., 1987 Eastlund et al. 361/231.
4817495 Apr., 1989 Drobot 89/1.
Primary Examiner: Issing; Gregory C.
Attorney, Agent or Firm: Foley & Lardner
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Claims
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What is claimed is:
1. A method for generating an AIM, comprising the steps of:
(a) creating avalanche ionization in the atmosphere using a heater antenna;
(b) refocusing said heater antenna to alter the altitude of said avalanche ionization by frequency shifting said heater antenna; and
(c) scanning said heater antenna to paint an avalanche ionization layer.
2. A method for generating an AIM as claimed in claim 1 wherein said heater antenna is focused in the near field.
3. An apparatus for generating an AIM comprising:
(a) a phased array heater antenna which is focused at an altitude to cause an avalanche ionization area to be created in the atmosphere;
(b) means for controlling frequency of individual radiators of said phased array heater antenna to refocus said altitude of said avalanche ionization area; and
(c) means for controlling phase of the individual radiators to scan said phased array heater antenna.
4. An apparatus for generating an AIM as claimed in claim 3 wherein said phased array heater antenna is focused to cause said avalanche ionization area to be substantially a line.
5. An apparatus for generating an AIM as claimed in claim 4 wherein said means for controlling phase moves said line substantially at a constant altitude and said means for controlling frequency moves said line to different altitudes.
6. An apparatus for generating an AIM as claimed in claim 4 wherein said phased array heater antenna is a rectangular array and said line is formed parallel to a long dimension of said rectangular array.
7. An apparatus for generating an AIM as claimed in claim 3 wherein said phased array heater antenna is focused to cause said avalanche ionization area to be substantially a point.
8. An apparatus for generating an AIM as claimed in claim 7 wherein said means for controlling the phase moves said point substantially at the same altitude and said means for controlling frequency moves said point to different altitudes.
9. An apparatus for generating an AIM as claimed in claim 3 wherein said phased array heater antenna is focused in the near field.
10. A method of generating an AIM comprising the steps of:
(a) focusing a phased array heater antenna at an altitude to cause an avalanche ionization area to be created in the atmosphere;
(b) controlling the frequency of individual radiators of said phased array heater antenna to refocus said altitude of said avalanche ionization area;
(c) controlling phase of the individual radiators to scan said phased array heater antenna.
11. A method of generating an AIM as claimed in claim 10 wherein said step of focusing causes said avalanche ionization are to be substantially a line.
12. A method of generating an AIM as claimed in claim 11 wherein said step of controlling phase moves said line substantially at a constant altitude and said step of controlling frequency moves said line to different altitudes.
13. A method of generating an AIM as claimed in claim 11 wherein said phased array heater antenna is a rectangular array and said line is formed parallel to a long dimension of said rectangular array.
14. A method of generating an AIM as claimed in claim 10 wherein said step of focusing causes said avalanche ionization area to be substantially a point.
15. A method of generating an AIM as claimed in claim 14 wherein said step of controlling phase moves said point substantially at the same altitude and said step of controlling frequency moves said point to different altitudes.
16. A method of generating an AIM as claimed in claim 10 wherein said step of focusing is performed in the near field.
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Description
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to generation of a Artificial Ionospheric Mirror (AIM), or a plasma layer in the atmosphere. The AIM is used like the ionosphere to reflect RF energy over great distances.
2. Description of the Related Art
In the past, the technique of using the ionosphere as a mirror to reflect radio waves, or RF energy, has given Ham Radio operators the ability to send transmissions over long distances. This technique has also provided radar systems the ability to look "over the horizon." Variations and fluctuations in the ionosphere, however, can render the effectiveness of such communications uncertain. Thus, the desirability of creating controllable plasma layers in the atmosphere for communications purposes has been recognized. See, for example, U.S. Pat. No. 4,686,605 issued to Eastlund and U.S. Pat. No. 4,712,155 issued to Eastlund et al.
Previous experiments directed toward creating plasma layers for communications have suffered from the inability to control the inclination of the plasma layer so that signals could be transmitted and received from various ranges. In other words, while one could create a plasma layer in the atmosphere at a lower altitude than the ionosphere, point to point communications would be limited in range based on the reflection angles of the transmitted and reflected signals.
SUMMARY AND OBJECTS OF THE INVENTION
In view of the limitations of the related art it is an object of this invention to generate a plasma layer that could be angled or tilted with respect to the horizon in order to affect signal transmission range.
The present invention provides a system and method for generating a plasma layer at controlled altitudes and inclinations that acts as an artificial ionospheric mirror (AIM) to reflect RF signals. The AIM increases the range and predictability with which RF energy may be reflected off the AIM for communications purposes. More specifically, a tiltable AIM is created by a heater antenna controlled in phase and frequency. The heater antenna phase shift scans a beam to paint a plasma layer. The heater antenna continually refocuses at a higher altitudes by frequency shifting to tilt the plasma layer.
BRIEF DESCRIPTION OF THE DRAWINGS
Further details of the present invention are explained with the help of the attached drawings in which:
FIG. 1 shows creation of an AIM by a heater antenna and use of the AIM for tracking aircraft and reflecting radio waves.
FIG. 2 shows a typical heater array.
FIG. 3 shows the spacial relationship for a heater array used in defining heater array focusing.
FIG. 4 is a graph showing that power is at its upper bound at the antenna focal point.
FIG. 5 shows generation of plasma by a heater array.
FIG. 6 illustrates generation of a plasma layer by scanning a heater antenna.
FIG. 7 illustrates generation of a tilted plasma layer by scanning and refocusing a heater antenna.
FIG. 8 shows generation of a plasma layer using a heater antenna to scan with a line rather than a point.
FIG. 9 shows the phase corrections to move the antenna focal point from 60 Km to 61 Km.
FIG. 10 shows the frequency corrections to move the antenna focal point from 60 Km to 61 Km.
FIG. 11 is a plot of altitude v. distance location of plasma without frequency chirping.
FIG. 12 is a plot of altitude v. distance location of plasma with frequency chirping.
FIG. 13 shows the power density change after refocusing using frequency chirping .
FIG. 14 graphs the free electron density v. altitude for an unfocused array.
FIG. 15 shows an antenna power pattern without grating lobes.
FIG. 16 shows an antenna power pattern with grating lobes.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates the creation and use of An Artificial Ionospheric Mirror (AIM) for tracking aircraft and reflecting radio waves. A heater antenna 1 radiates power causing avalanche ionization or breakdown releasing free electrons in the atmosphere to generate the AIM 2. The heater antenna 1 is an array which can be used to focus energy at varying altitudes and elevations to tilt the AIM 2 using phase and frequency control. The AIM 2 simulates the ionosphere 3 which is also used to detect "over the horizon targets" 5. In addition, the AIM 2 can reflect radio signals transmitted from a transmitter 6 to a receiver 7 over long distances.
A typical heater antenna is shown in FIG. 2. It consists of an array of multiple active radiating elements 10 having their individual phase and frequency controlled from a control module 12. The radiating element 10 is used here to represent all possible antennas, including, but not limited to, dipoles, slots, small or large horns, log-periodic antennas, large parabolic reflectors, etc.
FIG. 3 shows the spatial relationship for a focused heater array. To have the electric fields from all of the array elements focus, or arrive in phase at a distance R.sub.o in the near field of the array, it is necessary to correct the phase of each element to compensate for the phase delay difference from the center element due to the additional phase path W.sub.ij. If R.sub.o is much larger than the maximum D.sub.ij in FIG. 3, then the phase delay can be approximated in wavelength to be:
W.sub.ij =(D.sub.ij).sup.2 /(4*R*g) (1)
where g is the wavelength of the heater frequency. Equation 1 is referred to as the quadratic phase error. If this error is less than g/8 when the element (i,j) is on the outer edge of the array, then the distance R.sub.o is said to be in the far field of the array.
In order to focus the array at R.sub.o, it is necessary to have several wavelengths of phase error from the outer elements of the array. That is, the term "focus" is used in this context to mean that the electric field from the array is concentrated in a desired spatial region.
FIG. 4 shows the degree of focusing that can be accomplished. This is a vertical pattern of an array whose elements have been phase shifted to focus at 60 Km. The array has 400 elements with a total width and length of 2000 g. The peak of the pattern is determined by the 1/R.sub.o.sup.2 dependence.
The AIM ionization layer is created by using this focused power to ionize an area in the atmosphere, as shown in FIG. 5. The microwave breakdown of air occurs where free electrons gain enough energy from an electric field to generate additional free electrons until no more can be generated, thereby resulting in avalanche ionization, or breakdown. This causes the generation of a plasma layer 21. For example, a pulse of power from the heater begins to propagate in the z direction shown in FIG. 5. As the field propagates, more free electrons are generated. A breakdown point descends vertically from the focal point of the propagating field giving thickness to the ionized layer, or plasma layer, until all ionization stabilizes. This "clamping" creates a thin vertical plasma layer.
Simulation results show that when an array 20 is focused at a point 22, electric field power peaks at the focal point. Simulation results shows that given a focused microwave source avalanche ionization, or breakdown will occur at a power level 3-10 dB below the focal point power level.
To create an AIM, the heater array is focused at a desired altitude to maximize power at a point and thereby generate plasma. The heater antenna then "scans" the phase of each array element to move the focal point.
FIG. 6 illustrates creation of a noninclined AIM layer. The heater array 30 is first focused at point 31. The heater array scans horizontally by phase shifting to a point 32 creating an avalanche ionization line 33. Next, the heater array scans from a point 34 to a point 35 creating another avalanche ionization line 36. The heater array continues this process to create an ionization plane or AIM layer.
In order to form an inclined AIM cloud, each new ionization line must occur at a slightly higher altitude. By altering the phase or frequency of the array elements, the focal point can be moved up in altitude, as described below.
FIG. 7 illustrates creation of an inclined AIM. The heater array 40 is first focused at point 41. The heater array scans along the x direction to point 42 to generate avalanche ionization along line 43. Next, as in creation of a non-inclined AIM, the heater array scans along the x and y directions directly below point 44. The heater array 40 alters either phase or frequency to refocus to a higher altitude in the z direction to the point 44. The heater array then scans along the x axis to point 45 to create the avalanche ionization line 46. The heater array continues this process to create a tilted ionization plane or tilted AIM layer.
FIG. 8 shows that the preferred method of generating a plasma layer uses a heater antenna to scan with a line rather than a point. Scanning using a line is preferred since an AIM can be created in the atmosphere in less time. To create lines of ionization rather than points, a rectangular array 50 is used. In the array 50, radiating elements are focused only along the plane of the long dimension of the rectangular array, creating a line of ionization 53. The array is then scanned along the x-y axis and in altitude along the z axis to create another ionization line 55. More ionization lines are similarly generated to form a tilted AIM layer.
In order to create a tilted AIM it is necessary to refocus the heater array at successively higher altitudes. Moving the focal point by changing the phase of each element of the heater in a very precise manner is not practical. Moving the focal point away from the initial location requires changing the phase on each element. The phase change required is near the rms tolerance level, typically 1 degree. FIG. 9 shows the required phase corrections to move the focal point from 60 Km to 61 km. Elements 5, 10, 15, and 20 have distances 5d, 10d, 15d, and 20d, respectively from the center of the antenna, where d=25 meters It is clear from FIG. 9 that it is impractical to alter numerous antenna element phases to move the focal point to create tilted patches for AIM applications. 2000 elements may be required here to generate enough power to ionize the atmosphere.
The second method of refocusing is accomplished by first setting the phases of all elements for the initial focal point and then moving the focal point by changing the frequency rather than the phase. This frequency chirping method is less precise, but easier for hardware implementation because precise phases for 2000 elements need not be changed. FIG. 9 shows the required phase corrections to move the focal point from 60 Km to 61 Km. FIG. 10 shows that the focal point can be moved 100 meters by increasing the frequency approximately 1 Mhz. The resulting focal point power levels are not completely optimized, but simulation shows that there is less than a 0.1 db difference between the frequency shifted peaks and those obtained by phasing.
Tilting the AIM using frequency chirping is practical to achieve in a real system. FIG. 11 shows the plasma layer location with no frequency chirping. FIG. 12 shows the plasma location of the same heater creating a tilted AIM by increasing frequency from 550 MHz to 559.375 MHz while scanning horizontally. The result is a smooth patch with a 45 degree inclination.
While it is true that frequency chirping does not achieve the same power as phase focusing at the higher altitude, the difference for small frequency chirps is negligible. FIG. 13 shows actual power density data generated by a 300 MHz heater focused at 70 km with the frequency chirped to 308 MHz.
In the far field region, power meets its upper bound without focusing. For a far field or unfocused array, there is no way to raise the ionization altitude or create a tilted AIM. Ionization takes place at a point where there is enough power to initiate breakdown and where there is low enough neutral density (i.e. pressure). This usually occurs between 40 and 50 km altitude as shown in FIG. 14. Consequently, a near field focused antenna is required to create a controlled AIM.
The focused pattern is a picture of constructive and destructive interference of the fields from the elements of the array. Other interference positions, or grating lobes, outside the focal point occur when some of the array elements add up in phase. The power of grating lobes can be kept below that of the main lobe, or focal point, by having a large number of elements in the array and spreading them out over the array aperture. This is called thinning the array. For square arrays having 400 elements or more grating lobes can be kept down by 20 db or more from the focal point.
The degree of focusing depends on the ratio of focal range to aperture size. The half power width from peak "V" can be approximated as:
V=2*g*(R.sub.o /L).sup.2 (2)
where L is the length of the array which is assumed square for equation 2. The power gradient at the half power point "grad(P)" can be approximated as:
grad(P)=10/V(db/meter) (3)
For an AIM it is desirable that the power gradient be high because this directly determines the gradient of the electron density of the generated ionized cloud. The electron density must be high to avoid RF losses caused by absorption. Hence V be small, preferably less than 2 Km. A heater frequency of 300 MHz and a focal distance of 70 Km would project an aperture size greater than 2 Km. Note in equation 2 that array size scales with the square root of frequency.
Since a near field antenna is required, the near field of the heater antenna may be required to extend to reach distant points. This is accomplished by increasing the array size. It may not be economically feasible to fill this entire aperture with elements, hence a thinned array is utilized.
If a thinned array had its elements uniformly distributed, there would be many grating lobes in the radiation pattern of the array. These grating lobes can be eliminated by randomly spacing elements. However, random spacing puts power from the grating lobes into the average side lobe level. If no new elements are introduced when the aperture is increased, then the peak power of the main lobe remains constant and the main lobe receives less of the total power as its beamwidth decreases. In order to preserve the efficiency of the heater array, grating lobes must be utilized in creating the AIM cloud or the array can not be heavily thinned. FIG. 15 shows an array with uniform spacing having grating lobes. FIG. 16 shows an array with randomized spacing which eliminates the grating lobes.
Although the invention has been described above with particular reference to certain preferred embodiments thereof, it will be understood that modifications and variations are possible within the spirit and scope of the appended claims.
[Edited 2 times, lastly by Unhappy Trails on 08-20-2002] |
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Unhappy Trails
Joined: 10 May 2002
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United States Patent 4,817,495
Drobot April 4, 1989
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Defense system for discriminating between objects in space
Abstract
A defense system and a method for discriminating between armed re-entry vehicles and unarmed objects which are in close proximity of each other. The re-entry vehicles and the unarmed objects are bathed in a cloud of relativistic electrons with the resulting signatures from heavy objects, i.e., re-entry vehicles, being imaged directly. Detectors sense the location and identify of the re-entry vehicles and passes this information onto a weapons platform for tracking and interception.
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Inventors: Drobot; Adam T. (Annandale, VA)
Assignee: APTI, Inc. (Los Angeles, CA)
Appl. No.: 883223
Filed: July 7, 1986
Current U.S. Class: 89/1.11; 250/310; 250/358.1
Intern'l Class: G01N 023/00; H05C 003/00
Field of Search: 250/306,358.1,310 324/464 328/1 89/1.11,1.1
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References Cited [Referenced By]
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U.S. Patent Documents
3327124 Jun., 1967 Plum 250/306.
4320298 Mar., 1982 Buford et al. 250/358.
4393311 Jul., 1983 Feldman et al. 250/310.
4412967 Nov., 1983 Winterberg 89/1.
4686605 Aug., 1987 Eastlund 89/1.
Other References
"Particle Beam Weapons", Parmentola et al., 4/79, pp. 54-65, Scientific American, vol. 240, #4.
"Radiation Backscattering . . . Structure", Berk, S.; pp. 309-312, Materials Evaluations, vol. 24, #6, 6/66.
"Space-Based Ballistic-Missile Defense", Bethe et al., 10/84, pp. 39-49, Scientific American, vol. 251, #4.
Primary Examiner: Moskowitz; Nelson
Attorney, Agent or Firm: Faulconer; Drude
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Claims
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What is claimed is:
1. A method of discriminating between armed, reentry vehicles and unarmed objects in space, said method comprising:
transmitting electromagnetic radiation from the surface of the earth to the vicinity of the vehicles and objects to accelerate electrons present in space to create a cloud of relativistic electrons around said re-entry vehicles and said objects;
interacting said relativistic electrons with said reentry vehicles and said objects to thereby produce individual signature signals representative of said individual re-entry vehicles and said objects; and
detecting said signature signals for discriminating between said re-entry vehicles and said objects.
2. The method of claim 1 wherein said electromagnetic radiation is propagated by cyclotron resonance acceleration.
3. The method of claim 1 wherein said electromagnetic radiation is propagated surfatron acceleration.
4. The method of claim 1 wherein said electromagnetic radiation is propagated by beat acceleration.
5. The method of claim 1 wherein the electromagnetic radiation is propagated by plasma wake acceleration.
6. The method of claim 1 wherein said electrons are those situated in an inherent ambient plasma which surrounds said re-entry vehicle and said objects.
7. The method of claim 1 wherein said electrons are the products being outgassed by said re-entry vehicles and said objects.
8. The method of claim 1 including:
detecting only the signature signals from said armed, re-entry vehicles while ignoring the signatures produced by said unarmed objects.
9. The method of claim 1 wherein said electrons are accelerated to energies greater than 5 million electron volts.
10. The method of claim 8 wherein said signature signal are comprised of photons created by the interaction of said relativistic electrons with materials in said re-entry vehicles and said objects.
11. The method of claim 8 wherein photons are at a distance of at least 10-1000 kilometers from said interaction between said relativistic electrons and said reentry vehicles and said unarmed objects.
12. A defense system for detecting and discriminating between armed, re-entry vehicles and unarmed objects when in close proximity of each other in space, said defense system comprising:
means positioned on the surface of the earth for transmitting electromagnetic radiation from said surface of the earth to the vicinity of said vehicles and objects to thereby create a cloud of relativistic electrons of energies greater than 5 million electron volts around both said re-entry vehicles and said objects for interaction therewith whereby individual signature signals are produced from each object and each re-entry vehicle;
means for detecting said signature signals for identifying said re-entry vehicles from objects.
13. The defense system of claim 12 wherein said means for creating relativistic electrons comprises:
ground-based generators for generating electricity;
transmitter means powered by said electricity to generate electromagnetic radiation;
antennae means for focusing said electromagnetic radiation into said ambient plasma around said re-entry vehicles and said objects; and
a power source for powering said generators.
14. The defense system of claim 13 wherein said power source comprises:
natural gas.
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Description
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DESCRIPTION
1. Technical Field
The present invention relates to a method for discriminating between objects in space and more particularly relates to a defense system which utilizes ground based power to generate relativistic electrons which interact with objects in space to produce identifying signatures from said objects.
2. Background Art
Presently, the expected scenario for any large-scale intercontinental ballistic missile attack includes the deployment of a large number of decoys and penetration aids in a "threat cloud" around one or more armed, re-entry vehicles in an attempt to confuse any defense systems set up to counteract the armed missiles. The decoys and/or penetration aids can be launched simultaneously with the armed vehicles or can be deployed from a separate space-borne vehicle (sometimes called a "bus"). Since the total number of objects expected in a typical threat cloud may well exceed one hundred thousand, any truly effective defense system must include a system which is capable of "interrogating" all of the objects in the threat cloud and quickly discriminating between the deadly re-entry vehicles and the harmless decoys and penetration aids. By doing this, the defense system can ignore the decoys and penetration aids and concentrate all of its countermeasures on destroying or disabling th!
e armed missiles.
In addition to having the ability to distinguish unambiguously between armed and unarmed objects, an effective discrimination system must also be capable of responding quickly to any threat and must be capable of functioning in a nuclear background. Several such systems, both passive and active, have been proposed for this purpose wherein each object in a threat cloud is observed or acted upon in such a way as to produce an identifying signal (hereinafter called a "signature") from that object. These forms which these signatures may take fall into a wide spectrum of different types of signals ranging from radar-like wavelengths to hard x-rays and/or gamma rays and are derived from the objects in a variety of ways, some of which are:
(1) precise determination of orbital dynamics through tracking with radar, optical, or infrared instruments;
(2) differences in skin temperature due to inherent differences in decoy and re-entry vehicle heat capacity, these being based on infrared observations;
(3) active orbit perturbations coupled with orbital dynamics observations (i.e., high power lasers to cause skin ablation);
(4) active energy deposition (i.e., with lasers, hot electrons, etc.) to modify the observable thermal signature; and
(5) high power energy deposition to destroy decoys or to alter their trajectory from those of the re-entry vehicles in the threat cloud.
In each of the above systems, a signature of each object in a threat cloud is analyzed to identify that particular object. However, by having to observe and analyze each of the numerous objects in a threat cloud, each of these systems are characterized by the extremely large data flows required and the highly complex decision-making requirements of the battle management system of these defense systems. Accordingly, it is highly desirable to reduce these data flows and to simplify the discrimination of armed vehicles while maintaining the other requirements of an effective defense system.
Still further, previous proposed discrimination systems have all relied heavily on space borne equipment to observe and produce the signatures from the objects to be identified. For example, various beam generators have been proposed which are to be carried aloft by a satellite or the like to focus on and to direct a beam onto an object in a threat cloud to thereby produce a signature from that object. This exposure of such equipment makes it highly vulnerable to damage and makes continuing maintenance of the equipment difficult. Therefore, it can be seen that it is desirable to have as much of the defense system based on the ground as possible where it can be better protected and maintained.
The more conventional discrimination methods, such as differentiation of orbital mechanics, suffer from known countermeasures which block direct viewing of the object under interrogation. Examples of this are chaff to counter radar and sprays or aerosols to produce false infrared signals. The presence of a thermos-like skin may defeat schemes which differentiate on the basis of thermal capacity. It is therefore extremely advantageous to use methods which cannot be countermeasured without severe penalty for the offensive system.
DISCLOSURE OF THE INVENTION
The present invention provides a defense system and a method for detecting re-entry vehicles, discriminating between armed re-entry vehicles and unarmed decoys in close proximity of each other and the detection of re-entry vehicles in the presence of obscurants, which is basically ground-based and which is capable of functioning in possible hostile nuclear background. The basic concept of the present invention is to "bathe" the re-entry vehicles and the unarmed objects in a cloud of relativistic electrons. The resulting radiation signature from each object is such that heavy objects characteristic of the re-entry vehicles can be imaged directly. Detectors located away from the cloud of relativistic electrons sense the location and identity of the re-entry vehicles and passes this information onto a weapons platform or the like for tracking and interception. The present invention greatly reduces the amount of data that has to be handled and the computations required by one to!
two orders of magnitude since it allows the defense system to deal only with the actual threats.
More specifically, it is advantageous to locate such a discrimination and detection system in the likely corridor for ICBM trajectories, consequently a system could be located in Alaska, and fueled by the natural gas reserves that exist on the North Slope. The gas reserves can then be used to generate large amounts of electricty which, in turn, power a ground-based transmitter to generate electromagnetic (em) radiated energy. This em energy is propagated by ground-based antennae to excite and accelerate electrons which are present in space in the zone of interest. The em energy can be propagated and focused to a desired location in space by proper design of the antennae and there to accelerate electrons by any of several known means, e.g., cyclotron resonance acceleration. This technique can be used to excite electrons in the:
(1) ambient plasma in space to form a cloud of relativistic electrons around all of the objects or to form a stationary shield of relativistic electrons through which the object must travel, or
(2) the products which inherently outgas from objects in space to form individual clouds of relativistic electrons around each object.
The electrons are accelerated to energies greater than 5 million electron volts (e.g., 20 Mev) to create relativistic electrons which interact with the materials in the objects to thereby produce x-ray and gamma ray (i.e., photons) signatures from the objects.
A detector means (e.g., photon counting telescope) is positioned at some distance from the relativistic particle cloud and is set at an energy cut-off threshold so that only signatures representative of the heavy, re-entry vehicles will be sensed by the detector. The cut-off threshold will eliminate or ignore the lower energy signatures from the unarmed objects which allows the defense system to concentrate only on the armed vehicles. The detector means can be placed on individual weapons for final homing, in a payload accompanying the kill system which passes in formation to the individual weapons, or in a stand-off detector located far from the target region which passes information for further action to a satellite management system.
BRIEF DESCRIPTION OF THE DRAWINGS
The actual construction, operation, and apparent advantages of this invention will be better understood by referring to the drawings in which like numerals identify like parts and in which:
FIG. 1 is a schematical illustration of the detection and discrimination system of the present invention;
FIG. 2 is an idealized illustration of one embodiment of the present invention;
FIG. 3 is an idealized illustration of another embodiment of the present invention; and
FIG. 4 is an idealized illustration of still another embodiment of the present invention.
BEST MODES FOR CARRYING OUT THE INVENTION
Referring more particularly to the drawings, the basic components of the defense system of the present invention is schematically illustrated in FIG. 1. Ground facilities 10 are constructed at a selected strategic geographical location on the earth's surface 11. Facilities 10 includes one or more electricity generators 12 which are powered by fuel source 13. The various components will be discussed is greater detail below. The electricity generated by generators 12 drive transmitters 14 which, in turn, generate electromagnetic radiation at a wide range of discrete frequencies, e.g., from about 1 to about 2,000 Megahertz (MHz) depending on the particular embodiment of the concept.
The electromagnetic radiation from transmitters 14 is fed to one or more separate antennae 15 which, in turn, focus this energy onto threat cloud 16 which contains a large number of objects, i.e., armed vehicles 17 and unarmed decoys and penetration aids 18. The antennae system will be spread out over a large area (10's of kilometers) and most probably consist of phasable elements. The orientation and phasing of the antennae system will then determine the location at which the focused electromagnetic fields will exceed the conditions necessary for particle energization. At other locations in the path of the em radiation, the fields will be too weak to result in acceleration. As will be further explained below, the electromagnetic radiation will energize the ambient plasma in the threat cloud or the outgassing products from the objects to create relativistic electrons around the objects. Propagation of the radiation energies may be directly from antennae 15 through the ionosp!
here (line 19) or through one or more relay satellites 20 (lines 21) which may either reflect or re-beam the ground generated radiation.
The relativistic electrons interact with the objects which produce very unique x-ray and/or gamma ray signatures which only come from the heavy armed, re-entry vehicles 17 as will be explained below. As shown, detector means 22 is positioned at distances of from 10 to 1000 kilometers (Kms) from the threat cloud 16 but in some instances, the detector means may be mounted directly on close-in weapon platforms. Detector means 22, scans the threat cloud 16 and picks up and pinpoints each object emitting a signature representative of an armed vehicle 17. Detector means 22 ignores the other objects 18 in the threat cloud. Also, the counting rate for the expected x-ray and gamma ray signals (i.e., photons) are high enough to exceed the nuclear background by a comfortable margin. Once re-entry vehicles 17 are identified, this information is passed from detector means 22 to a battle management system 23 or to a weapons platform 24 for further defensive action. Now that the overall as!
pects of the present defense system have been described, a more detailed description of the components and operation of the system will now be discussed.
A large amount of power (e.g., up to 10.sup.12 watts) in continuous or pulsed power for finite periods of time will be required for implementing the present invention. Generation of the needed power is within the state of the art. Although the electrical generators 12 necessary for the practice of the invention can be powered by any known fuel source 13, for example, by nuclear reactors, hydroelectric facilities, hydrocarbon fuels, and the like, this invention, because of its very large power requirement in certain applications, is particularly adapted for use with certain types of fuel sources which naturally occur at strategic geographical locations on the earth. For example, large reserves of hydrocarbons (oil and natural gas) exist in Alaska and Canada. In Northern Alaska, particularly the North Slope region, large reserves are currently readily available. Alaska and Northern Canada also are ideally located geographically for the placement of the present defense system. !
Thus, in Alaska, there is a unique combination of large, accesssible fuel sources at a very desirable defense location.
Further, a particularly desirable fuel source for the generation of very large amounts of electricity is present in Alaska in abundance, this source being natural gas. The presence of very large amounts of clean-burning natural gas in Alaskan latitudes, particularly on the North Slope, and the availability of magnetohydrodynamic (MHD), gas turbine, fuel cell, electrogasdynamic (EGD) electric generators which operate very efficiently with natural gas provide an ideal power source for the unprecedented power requirements of certain of the applications of this invention. For a more detailed discussion of the various means for generating electricity from hydrocarbon fuels, see "Electrical Aspects of Combustion", Lawton and Weinberg, Clarendon Pres, 1969.
Put another way, in Alaska, the right type of fuel (natural gas) is naturally present in large amounts and at just the right location for the most efficient practice of this invention, a truly unique combination of circumstances. Electricity from generators 12 is supplied to power the transmitters 14 to generate microwave or radio frequency (r.f.) energy which is transmitted by antennae 15. Antennae 15 may be of any known construction for high directionality, for example, a phased array, beam spread angle (.theta.) type. See "The MST Radar at Poker Flat, Alaska", Radio Science. Vol. 15, No. 2, March-April 1980, pps. 213-223, which is incorporated herein by reference. However, it is well understood by those knowledgeable in the art that the actual design of any particular antennae will depend, in part, on the frequency of electromagnetic (em) radiation (e.g., H.F.-U.H.F.) to be used.
To create the required relativistic electrons (i.e., electrons whose mass is increased due to high velocities) within thread cloud 16, the electrons in the ambient plasma or outgassing products therein have to be excited or accelerated to energies above 5 MeV (million electron volts) (e.g., 20 MeV). The energy threshold is determined by the range of electrons in various materials and by the radiation yield of various materials. Above 5 Mev, electrons penetrate to the interior of the object under observation and the signature can only be masked by the inclusion of heavy radiation shielding. Such shielding is impractical for decoys because it exerts a tremendous weight penalty on the ICBM boost system. The radiation yield increases significantly above 5 MeV and it is therefore desirable to accelerate electrons to the .about.10-50 MeV range where a broad peak in yield exists. To be effective in the present invention, the electrons will need to be accelerated to the required ene!
rgies in an extremely short distance on the order of or shorter than 10 to 10.sup.4 meters. To effect such quick and efficient acceleration of the electrons, several techniques are available for transmitting electromagnetic radiation from the ground-based transmitters to interact with electrons which intercept the threat cloud. These include:
(1) Cylotron Resonance Acceleration (CRA) which utilizes the interaction of an em wave with the plasma electrons. The transmitted radio-frequency radiation produces time-varying fields (electric and magnetic) and the electric field accelerates the electron. For a more detailed description of the physical phenomenum involved in the technique, see "Controlled Thermonuclear Reactions", Glasstone and Lovberg, D. Van Nostrand Company, Inc., Princeton, N.J., 1960.
(2) Surfatron acceleration which creates an electrostatic wave perpendicular to the magnetic field. The electrons trapped in the wave see an electric field which accelerates them across the wave front. As long as the electrons cannot "detrap" themselves, the resulting acceleration will be limited only by the size of the wavefront. For a further discussion of surfatron, see "dc Acceleration of Charged Particles by an Electrostatic Wave Propagation Obliquely to a Magnetic Field", Sugehata et al., PHYSICAL REVIEW LETTERS, Vol. 52, No. 17, Apr. 23, 1984, pg. 1500.
(3) Beat Acceleration (BA) relies on "beating" two em waves of different frequencies to generate a high phase velocity electrostatic wave. This wave will trap and accelerate electrons until they get out of phase with the wave. For a further discussion of BA, see "Excitation of Plasma Waves in the Laser Beat Wave Accelerator"; Tang et al., Appl. Phys. Letter 45, 15 Aug. 1984, pg. 375.
(4) Plasma Wake Acceleration (PWA) uses one frequency wave in the form of a wave packet. The em wavepacket of half the plasma wavelength resonantly excites the plasma wave. The em packets are repeated at timed intervals to produce a strong wave. For further description of PWA, see "Forward Raman Instability and Electron Acceleration", Joshi et al., PHYSICAL REVIEW LETTERS, Vol. 47, No. 18, Nov. 2, 1981, pg. 1285.
While one or a combination of the above acceleration techniques may be used for creating the required relativistic electrons, the accessibility of the transmitted em energy to the interaction region must be considered. As set forth above, the em energy can be transmitted to the interaction region (threat cloud 16) directly from the ground based transmitters, through satellites borne mirrors 20, or a combination of both. The em energy should be transmitted to the interaction region with minimal losses which will depend on the selected antennae configuration, the location of the interaction region, and the required frequency of the transmitted energy. In general, high frequencies (e.g., above 10 MHz) have the advantage of avoiding problems with accessibility or unwanted D-region absorption. Unwanted nonlinear backscattering or absorption processes with power thresholds can be avoided by using different propagation paths to the interaction region for part of the necessary power!
.
Once the electrons in threat cloud 16 are accelerated to relativistic velocities, the relativistic electrons interact (impact) with the objects 17 and 18 in the threat cloud to produce discriminating signatures. These signatures are based on the mass per unit area of an object. That is, the x-ray flux generated by these interaction (i.e., that detected by detector means 22) is roughly proportional to the mass per unit area of the material from which the object is constructed. In addition, the x-ray spectrum is sensitive to the presence of heavy and high atomic weight (Z) elements found only in armed, re-entry vehicles 17. These factors would require a very, if not prohibitive, high weight and cost penalty to construct a decoy or penetration aid which would simulate a signature similar to a re-entry vehicle.
The interaction of the relativistic electrons with heavy, high Z objects (armed vehicles) will produce high energy Bremsstrahlung (i.e., continuous radiation emitted by charged particles, namely electrons, as a result of deflection by Coulomb fields or other particles) which is quite susceptible to detection by suitably designed gamma ray and/or x-ray detector telescopes (detector means 22). Lightweight, low Z balloons and decoys will produce little or no such signals and accordingly are effectively ignored by detectors 22.
More specifically, detectors means 22 is preferably a photon-counting telescope of the type which detects high energy photons even in an environment dominated by background prompt and residual radiation from a large number of nuclear bursts to discriminate between the radiation (i.e., signatures) from reentry vehicles and that from unarmed objects. Further, to determine the direction from which an incidental photon came, the detectors must be capable of some degree of angular resolution. The resolution of the detector is determined by distance to the threat cloud. To locate an object within a ten meter sphere, the resolution must be better than .DELTA..theta.=10.sup.-2 /R where R is the distance between the object and the detector in Kms. For detectors at ranges of 1000 km .DELTA..theta..ltorsim.10.mu. radians. The Bremsstrahlung photons, coming from signatures produced by interaction of the relativistic electrons with an object, will be uniformly spread from zero to the max!
imum energy of the relativistic electrons. However, the energy threshold detector of detector means 22 will be set at energy level equal to the minimal valves of the signatures expected from the armed vehicles and will only detect and analyze those signatures at or above this threshold energy level. Therefore, detector means 22 will quickly detect and pinpoint vehicles 17 (high energy signatures) while ignoring objects 18 (low energy signatures, if any) in the threat cloud.
As a further explanation of how the interaction of the relativistic electrons generate or produce identifying signatures from the objects, consider the following example. A 20 MeV electron has a range in matter of about 10 gm/cm.sup.2. The "thickness" of a typical re-entry vehicle 17 is like 20 to 40 gm/cm.sup.2. Thus, a relativistic electron will be stopped by the re-entry vehicle 17, converting a major fraction of its energy into photons. On the other hand, the same relativistic electron will sail through a lightweight decoy 18 or a balloon producing, relatively speaking, almost no Bremsstrahlung signal. It follows that a five-to-ten percent by weight decoy will produce a five-to-ten percent, relative to the re-entry vehicle, signal if made from high Z material. Since the decoy or balloon is mostly low Z material, the photon signal is much less since all of the electron energy is dissipated in loss to ionization.
For example, for aluminum (Z=13), the loss to radiation dominates above an energy E=61.5 MeV. For uranium (Z=92), the crossover energy is only 8.7 MeV. Thus, for lightweight, low Z decoys, the efficiency of conversion of electron energy to photons in an object is significantly less than 1 while the conversion efficiency for a re-entry vehicle with uranium is approximately 1.
Detectors 22 are located at a distance (e.g., 10-1000 km) from the cloud of relativistic electrons and should not be immersed therein.
Again turning to the drawings, FIG. 2 graphically illustrates a first specific embodiment of the present invention wherein a sperical cloud 30 of relativistic electrons are created around a "bus" 31 which is deploying a number of decoys, penetration aids, balloons, chaff, etc. 32 around and in the vicinity of armed, re-entry vehicles 33. By tracking bus 30 with antennae 15, cloud 30 will move dynamically with bus 31 or its ballistic trajectory. Decoys, etc. 32 are identified on a time less than 1 second since the signature (i.e., photon flux) at detector means 22 is less than the value of the signature expected from an armed vehicle 33. Decoys 32 are thereafter ignored by the discrimination system which will continue to track only vehicles 33.
To insure that all objects will encounter relativistic electrons in cloud 30, the radius L of cloud 30 should be on the order of 1 kilometer (km) when the relative speed of the objects with respect to the speed of cloud 30 is on the expected order of Ur.apprxeq.1 km/second.
Cloud 30 of relativistic electrons (5-10 MeV) is formed by energizing from 10.sup.-3 to 10.sup.-4 of the ambient plasma having an electron density (n.sub.e) of from 10.sup.4 to 10.sup.5 by applying r.f. or microwaves from ground based transmitters as discussed above. The amounts of power required, confinement time, etc., can be calculated from known relationships. For example, for a baseline example where: Ur=1 km/sec; speed of object=1 km/sec; L=1 km; t=1 sec.; observing or dwell time=10 sec.; density of vehicle 33 material (n.sub.R)=10 #/cm.sup.3 ; omnidirectional flux above 5.5 MeV (F)=10.sup.11 #/cm.sup.2 sec:
(a) Total energy in cloud 30=8 kilo joules
(b) Confinement time=1.6 msec
(c) Power requirement=50 to 500 MW
(d) Total energy requirement for 1-5 dwell time=1-10 GJ.
The minimum time T for building cloud 30 can be expressed as:
T=e/p msec
wherein:
e=total energy in cloud 30 in kJ and
P=total power requirement in GW which will normally range between 1 to 100 .mu. sec.
During this time, bus 31 moves a distance less than a few tens of meters. Due to the power considerations, it is desirable to use as small of cloud 30 as the focusing of the ground based energy and the acceleration length allows.
FIG. 3 illustrates a further specific embodiment of the prevent invention wherein the electrons in outgassing products from an individual object 40 are energized by ground-based energy to form cloud 41 of relativistic electrons for interaction with object 40 to produce a signature 42 therefrom. Due to the high vacuum conditions of space, all materials will inherently give off (i.e., outgas) gases which are otherwise entrapped in the material at atmospheric conditions. These gases will normally form a cloud extending to a distance of 2-20 meters around object 40 which will have an estimated particle density N.sub.o of 10.sup.11 per cubic centimeter.
In this embodiment, electromagnetic radiation from antennae 15 ionizes the outgassing products to form cloud 41 of relativistic electrons of 10 MeV. From the total relativistic electron density N.sub.e of 4.times.10.sup.14, half will interact with object 40 to generate a signature 42 which is detected by detector means 22.
The total energy requirement for this embodiment to create a cloud having an 10 MeV electron density of 4.times.10.sup.14 is 32 joules. In order to deliver this energy on the required time scale of 10.sup.-5 to 10.sup.6 seconds, the required power will be on the order of 1-5 MW.
The dwell time per object 40 will be very short. The most strenuous requirements for this embodiment are on the physics of the acceleration. Namely the acceleration length should be Lo.apprxeq.1-10 m. This embodiment requires rather high frequency microwaves, since the spot size for efficient energization should be of the order of 1-4 m.sup.2.
FIG. 4 illustrates still another embodiment wherein a stationary layer or shield 51 of relativistic electrons are positioned in the path of a threat cloud (dotted line 50). Decoys and armed re-entry vehicles in the threat cloud will produce signatures dependent on their respective weight per unit area similarly as discussed above. A layer thickness X of 10 km will require n.sub.R =10 cm.sup.-3. The stationary shield 50 requires energizing electrons at an altitude between 200-1000 km by r.f. energy from ground-based transmitters and storage in naturally-occurring radiation belts. The energization altitude will also be the mirror point M if the energy transfer is perpendicular to the magnetic field. The guiding center of the trapped electrons executes a bounce motion between the northern and southern mirror points with a bounce time t.sub.b .apprxeq..multidot.2 sec, while drifting eastward with a drift time t.sub.d .apprxeq.1000 sec. Depending on whether the layer build up tim!
e is longer than t.sub.d, the layer will be diluted by forming drift shell 51. Once shield 51 is established, object 50 passing therethrough will react with the relativistic electrons in shield 41 to produce signatures which are detected by detector means 22 which is positioned below and out of shield 50.
While the present invention has been described for discriminating between armed and unarmed vehicles in a threat cloud during an impending attack, it can also be employed to "interrogate" orbiting satellites to determine if any of said satellites may be carrying nuclear weapons for future launch. Again, a cloud of relativistic electrons would be created around the satellite of interest for interaction therewith to produce a signature from that satellite which, when analyzed, would reveal the nature of the materials contained in the satellite.
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United States Patent 4,873,928
Lowther October 17, 1989
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Nuclear-sized explosions without radiation
Abstract
A method for producing a high yield explosion without radioactive fallout comprising filling an expendible structure with an explosive mixture of a combustible gas (e.g. methane) and an oxidizer gas (e.g. oxygen) and then detonating said mixture.
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Inventors: Lowther; Frank E. (Plano, TX)
Assignee: APTI, Inc. (Los Angeles, CA)
Appl. No.: 062020
Filed: June 15, 1987
Current U.S. Class: 102/323; 102/324; 149/109.2; 434/218
Intern'l Class: F42B 003/00
Field of Search: 149/109.6,109.1,109.2 102/323,324 434/218
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References Cited [Referenced By]
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U.S. Patent Documents
2811431 Oct., 1957 Zwicky et al. 149/1.
2886424 May., 1959 Hyslop, Jr. 149/1.
3188253 Jun., 1965 Patrick 149/1.
3222230 Dec., 1965 Hebenstreit et al. 149/1.
3259532 Jul., 1966 Reynolds et al. 149/1.
3670494 Jun., 1972 Papp 60/23.
3680431 Aug., 1972 Papp 176/1.
4291623 Sep., 1981 Robinson et al. 102/310.
4393509 Jul., 1983 Merkel et al. 376/156.
Other References
Austin et al., Explosive Hazard of Aluminum-Liquid Oxygen Mixtures, Jour. Chem. Ed., vol. 36, #2, Feb. 1959, pp. 54-57.
Primary Examiner: Nelson; Peter A.
Attorney, Agent or Firm: Faulconer; Drude
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Claims
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What is claimed is:
1. A method for producing a violent and destructive explosion having high shock energies comprising:
partially filling an expendible structure with an initial mixture of combustible gas and an oxidizer gas in concentrations rich in said combustible gas so that said initial mixture is incapabale of burning or exploding;
mixing additional oxidizer gas into said initial mixture after said initial mixture is in place and contained within said structure to thereby create an explosive mixture within said structure; and
detonating said explosive mixture to produce said explosion and thereby destroying said expendible structure.
2. The method of claim 1 wherein said combustible gas is comprised of methane.
3. The method of claim 1 wherein said combustible gas is comprised of a mixture of methane and hydrogen.
4. The method of claim 2 wherein said oxidizer gas is comprised of oxygen.
5. The method of claim 4 wherein said additional oxidizer gas is mixed with said initial mixture by flowing oxygen gas into said structure after said initial mixture is in place within said structure.
6. The method of claim 4 wherein said step of mixing additional oxidizer gas into said initial mixture comprises:
positioning a container of liquid oxygen within said initial mixture within said structure;
positioning an explosive means within said container; and
detonating said explosive means to vaporize and disperse said liquid oxygen into said initial mixture.
7. The method of claim 1 wherein said explosive mixture is detonated by exploding conventional explosives positioned within said structure.
8. The method of claim 1 including:
dispersing dust-like particles into such explosive mixture within said structure; and
igniting said dust-like particles to detonate said explosive mixture.
9. The method of claim 8 wherein said dust-like particles are comprised of aluminum.
10. The method of claim 1 wherein said explosive mixture is detonated by exploding bridge wires positioned within said structure.
11. The method of claim 1 including:
positioning a mesh of metallic, wire-like filaments throughout said structure; and
igniting said mesh to detonate said explosive mixture.
12. The method of claim 1 wherein said mesh is comprised of zirconium.
13. The method of claim 1 wherein said structure is comprised of an inflatable envelope.
14. The method of claim 13 wherein said envelope is spherical inconfiguration when fully inflated.
15. The method of claim 1 wherein the energy yield of said explosive is equivalent to one kiloton or greater of T.N.T.
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Description
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DESCRIPTION
1. Technical Field
The present invention relates to a method for producing explosions from an explosive gas mixture which has a shock yield comparable to a nuclear explosion but one which produces no radioactive fallout.
2. Background Art
Between 1945 and 1960, the United States exploded nuclear devices which had a total yield equivalent to approximately 200 megatons (MT) of trinitrotoluene (T.N.T.). Tests conducted by other countries during this time brought the total yield of nuclear explosions to approximately 400 MT. It was quickly recognized that such testing could not continue since each nuclear explosion produced radioactivity that seriously threatened the environment. To protect the environment from such radioactive fallout, most of the world's nuclear powers signed the Nuclear Test Ban Treaty in 1963 which prohibited nuclear explosions in the atmosphere, underwater, and in space. Since that time, it is believed that substantially all nuclear explosions have been carried out underground.
The necessary prohibition against above-ground testing of nuclear explosives, however, has created situations where alternates to such explosions are needed. For example, all of the sophisticated communication systems, defense systems, weapon systems, etc. that have been designed and built for the military since 1963 have never been tested in their ultimate operating environments, i.e. under nuclear blast conditions. Obviously, any such testing has to be simulated through theoretical studies and/or under laboratory conditions. Radiation dosages and electromagnetic pulses which simulate those from nuclear explosions have been produced in shielded laboratories but the extreme shock energies which can be expected from nuclear explosions, e.g. 1 kiloton (KT) or larger, have not been satisfactorily duplicated. Without realistic testing, the question will always remain as to whether or not a particular system or component will survive a nuclear explosion. To provide such realistic!
testing with conventional explosions is impractical as will become obvious from the following discussion.
The conventional explosive, T.N.T., is the recognized standard of measurement and comparison for both nuclear and non-nuclear explosions. That is, the exploding of a kiloton (KT) or 2,000,000 pounds of T.N.T. releases 4.1.times.10.sup.9 Btus. It follows that the exploding of any material that release 4.1.times.10.sup.9 Btus is referred to as a 1 KT explosion. To amass 1 KT of T.N.T. at a single test site, in itself, is an ambitious and dangerous undertaking. For example, it is esimtated that it would take a 20-boxcar train to transport this amount of T.N.T. and the risks involved with such a shipment from a manufacturing or storage facility to the test site are self evident.
Further, when detonated, one volume of T.N.T. suddenly converts to 1000 volumes of gas. The speed and uniformity of "burn" and therefore the violence of T.N.T. depends upon the uniformity of the ignition method. Normal sized T.N.T. charges explode in microseconds but massive T.N.T. charges may take much longer due to the practical problems involved in uniform ignition. The transportation and the uniform detonation problems of large masses of T.N.T. makes its use as a source for simulated, nuclear-sized explosions both unattractive and impractical.
Accordingly, to produce a practical, non-nuclear explosion having nuclear-sized shock yields, the following criteria would seem imperative. First, there must be a reliable source of an explosive which is readily available in adequate quantities to support a continuing test program. Next, the explosive must be capable of being safely and reliably transported from its source to a remote test site. Further, a relatively inexpensive, expendible, test structure must be provided in which the explosive can be loosely contained until detonated. Lastly, the explosive must be capable of relatively instant and uniform detonation so that the violence of the blast adequately simulates that of a nuclear explosion.
DISCLOSURE OF THE INVENTION
The present invention provides a method for producing an explosion which yields shock energies equivalent to nuclear explosions but one which generates no radioactive fallout. Basically, the present invention utilizes a commonly available combustible gas, e.g. natural gas, methane, etc., mixed with a commonly-available oxidizer gas, e.g. oxygen, air, etc., as the explosive mixture for a large scale explosion. Methane, e.g. natural gas, is readily available in large quantities which can quickly and easily be transported to a remote test site by a common pipeline or the like.
More specifically, the present invention provides a method for producing an explosion by filling a large, expendible structure, e.g. an inflatable envelope, at a test site with an explosive mixture of methane and oxygen and then detonating said mixture. To provide a relatively safe operating environment during the filling operation, the envelope is first partially filled with an initial filling mixture comprised of methane and oxygen wherein the concentration of methane is too rich for the mixture to either burn or explode. After the initial filling mixture is in place, the mixture is "armed" or "topped-off" with additional oxidizer gas, e.g. oxygen, either in gas or liquid form, to change the relative concentration of methane and oxygen to one which will readily explode when detonated.
A plurality of detonation means can be used to effect a relatively unfiorm detonation front across the mixture within the envelope. Such means include conventional explosives, exploding bridge wires, dipole antennae activated by radio frequencies, metallic or organic dust particles, and/or metallic filaments dispersed throughout the explosive mixture.
BRIEF DESCRIPTION OF THE DRAWINGS
The actual construction, operation, and the apparent advantage of the invention will be better understood by referring to the drawings in which like numerals identify like parts and in which:
FIG. 1 is a schematical section of a test site having apparatus for inflating an envelope with a combustible gas-oxidizer gas mixture;
FIGS. 2-9 are schematical sections of a variety of different means for detonating an explosive gas mixture within the envelope of FIG. 1; and
FIG. 10 is an illustration of the envelope of FIG. 1 at a position above the surface.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring more particularly to the drawings, FIG. 1 discloses a test stand 10 comprised of base conduit 11 which is anchored into the ground 12 by any suitable means. A gas-tight, expendible, test structure, e.g. flexible envelope 13, has a filling inlet 14 which is secured in a fluid-tight relationship over the upper end of conduit 11. Conduit 11 has a manifold 15 connected thereto which, in turn, has two inlets 16, 17. Inlet 16 is connected to a combustible gas blower 18 while inlet 17 is connected to an oxidizer gas blower 17.
Preferably, the combustible gas is one that is naturally-available in large quantities and is one that can easily and safely be transported to the test site. For example, large quantities of natural gas, i.e. methane, are readily available in several geographical areas. Especially attractive are the huge quantities of methane in the North Slope Area of Alaska since there are remote areas nearby which are suitable as a test site. The methane can be produced and safely transported to the test site by a common pipeline. However, the test site does not have to be in close proximity to the methane production area since the methane can be gathered and safely pipelined for long distances as is now commonly done in supplying energy to areas remote from the production area. In the following descriptions, methane will be used in interchangeable with combustible gas and oxygen with oxidizer gas but, it should be understood, that obvious equivalents of these gases are intended to be cov!
ered hereunder.
A methane-ozygen mixture will neither burn nor explode if the methane concentration (CH.sub.4) is less than 5.4% or greater than 59.2% by volume. Accordingly, blower 18 feeds methane from pipeline 29 and blower 19 feeds oxygen from line 21 into manifold 15 at rates whereby the resulting mixture in manifold 15 is comprised of approximately 59.2% methane and 40.8% oxygen by volume. This initial filling mixture, which will neither burn nor explode, then flows into envelope 13 to fill the envelope to approximately 85% of its total capacity. By using a nonexplosive gas mixture to initially fill the envelope to near its capacity, the test system remains "unarmed" and the risk of a disastrous accident during filling is minimized. Also, the partially-filled envelope can be left in this condition for extended periods with little risk.
Just before a test explosion is to be carried out, the methane-oxygen mixture in envelope 13 is armed or "topped-off" by flowing only oxygen through manifold 15 until envelope 13 is filled to capacity. At this time, the mixture in envelope 13 will be comprised of approximately 50% methane and 50% oxygen, which is a highly explosive mixture. A detonation means within envelope 13 (not shown in FIG. 1) is actuated and a violent explosion results. The means for detonating the gas mixture may any one of the several means which are described in detail below.
To more fully understand the present invention, a specific example for producing a nonnuclear explosion having a shock yield equivalent to 1 KT of T.N.T. will now be set forth. A base conduit 11 having a diameter of 9.5 feet is securely anchored in ground 12. A 110-horsepower (h.p.) blower 18 supplies methane through inlet 16 (7.3 feet diameter) into manifold 15 at a rate of approximately 2100 cubic feet per second (CF/sec) while a 75-h.p. blower 19 supplies oxygen through inlet 17 (6 feet diameter) into manifold 15 at a rate of approximately 1420 CF/sec.
To assure proper gas mixing and agitation, the mixture (59.2% methane-40.8% oxygen by volume or CH.sub.4+ 0.689 0.sub.2) flows into envelope 13 as an initial filling mixture at a linear velocity of 50 feet/sec. Inflatable envelope 13 is comprised of DuPont 6/6 reinforced Nylon having a thickness of 2.42 mils. The reinforced Nylon will not rupture if punctured, as a rubber ballon would, but instead will only allow the gas to leak slowly through the puncture itself. When completely inflated, envelope 13 is spherical with a diameter of 305 feet and a total capacity of 14.9.times.10.sup.6 CF. When empty, envelope 13 will weigh approximately 1.29 tons. It will take approximately one hour at the above rates to fill envelope to approximately 85% of its total capacity with the non-explosive mixture. At this point, envelope 13 contains 12.6 million cubic feet (MMCF) of gas mixture of which approximately 7.5 MMCF is methane and 5.1 MMCF is oxygen.
Preferably, a short time before the test is to be conducted, the mixture is envelope 13 is "armed" or topped-off with additional oxidizer gas, oxygen, to provide a highly explosive mixture of approximately 50% methane-50% oxygen. To accomplish this, approximately an additional 2.32 MMCF of oxygen is supplied through manifold 15 by blower 19 at approximately 1420 CF/sec. In approximately 27 minutes, envelope 13 will be fully inflated with the explosive methane-oxygen mixture and will have an internal pressure of approximately 0.1 psi above the ambient pressure. The mixture is then detonated by any of the means described below.
It is estimated that when a 50% methane-50% oxygen mixture explodes, 1 MMCF of mixture yields energy equivalent to 0.0671 KT of T.N.T. Accordingly, the 14.9.times.10.sup.6 CF volume within envelope 13 will yield energy equivalent to 1 KT of T.N.T.
The speed and uniformity of "burn" and therefore the violence of any explosion depends upon the uniformity of the detonation method used in initiating the explosion. If all of the available chemical energy is to be released in an explosion, the combustion front must propagate across the entire combustible gas volume without being extinguished. It is the chemical heat release in the combustion front that generates and supports a faster shock front. If the combustion front is stopped or interrupted for any reason, the explosion will stop or will be interrupted.
Turning now to FIGS. 2-8, various means for detonating the explosive mixture in envelope 13 are disclosed. In FIG. 2, a charge 25 of a conventional explosive such as T.N.T. is positioned at the approximate center of envelope 13 on a support 26 and is sized to provide rapid detonation of the volume of gas in envelope 13. Charge 25 may be prepositioned within the envelope before inflation begins. Charge 25 is denotated in a conventional manner by an electrical firing pulse through line 26.
FIG. 3 illustrates a modification of the present invention wherein the test system is both armed (i.e. topped-off with oxygen) and denotated substantially simultaneous. Envelope 13 is partially inflated with a non-explosive, methane-oxygen mixture in the same manner as described above. A charge 28 of conventional explosive, e.g. T.N.T., is positioned within container 29 which is positioned at the center of envelope 13 on support 30 and which is filled with additional oxidizer gas. The additional oxidizer gas is preferably in concentrated form, e.g. compressed oxygen gas on liquid oxygen (LOX) 31. If LOX is used, charge 28 is sized so that when detonated by an electric pulse through line 32, the LOX will be vaporized to provide and dispurse the "arming" oxygen throughout the mixture in envelope 13. For the specific example described above, a charge 28 of 9500 pounds of T.N.T. in a spherical shape having a diameter of 5.7 feet is positioned within container 29 having a diamete!
r of 17.9 feet which, in turn, is filled with 103.5 tons of LOX. These amounts are calculated knowing the heat of vaporization of LOX to be 92 Btus/pound and that the exploding T.N.T. will provide 2000 Btus/pound.
FIG. 4 discloses another detonation means for initiating the explosion of the methane-oxygen mixture in envelope 13. Lengths of detonating cord 33, e.g. Ensign-Bickford "Primacord" by DuPont, is secured to the inner surface of envelope 13 along various circumferences (only two shown). The cords 33 are secured in position before inflation and additional lengths 33a (only one shown) can be suspended from the inside of the top of envelope so that they will hand downward through the mixture when envelope 13 is inflated. Detonating cord is a flexible cord that contains a center core of a conventional explosive, e.g. pentaerythritol tetranitrate (PETN), which denotates at a velocity of 22,000 feet per second and may contain up to 400 grains of explosive per foot, enough to trigger an explosion. Cords 33, 33a are denotated by a conventional detonator, e.g. blasting caps, which is actuated by an electrical pulse through line 34.
FIG. 5 discloses still another means for detonating the mixture in envelope 13. A plurality of bridge wires 35 (only two shown) are looped within envelope 13 and attached at the inside of the upper surface thereof before inflation so that they will extend across the envelope when it is inflated. Investigations into the use of exploding bridge wires have revealed some very unique features thereof such as the capability of (1) injecting energies in the 10 kilocalories and greater per mole range in submicrosecond time intervals and (2) producing high energy which, in turn, imparts high velocity to the physical mass of the reactants in contact with the wire. Accordingly, an exploding wire provides a way of concentrating large amounts of energy in a small space. Typically, a bank of capacitors (not shown) are charged to a high voltage level. The capacitors are then discharged through lines 37 into wires 35. The current through the wires is many magnitudes greater than that necess!
ary to fuse the wire. The extreme resistive heating in the wire causes a mean instantaneous vaporization of the wire which creates a shock wave in the atmosphere surrounding the wire to thereby initiate an explosion of the mixture in envelope 13.
FIG. 6 discloses a still further means for detonating the explosive mixture in envelope 13. A one-shot, radio frequency transmitter 40 is positioned at the center of envelope 13 on support 41. A plurality of center-fed, dipole antennae 42 extend outward to the inner surface of enelope 13 which may be coated with a thin metallic layer 43, e.g. aluminum. A single extremely high energy radio-frequency pulse is delivered to transmitter 40 through line 43 which, in turn, transmits the energy through dipole antennae 42. Since the energy is several orders of magnitude higher than antennae 42 are designed to handle, antennae 42 and metallic layer 43 will vaporize, basically in the same manner as an exploding bridge wire as described above.
FIG. 7 discloses another means for detonating the explosive mixture in envelope 13. A center electrode 44 is positioned at the center of envelope 13 on support 45 and the inner surface of envelope 13 is coated with a thin metallic layer 46, e.g. zirconium, to act as a second electrode. A mesh of thin wire-like, filaments of metal, e.g. zirconium, is positioned within and throughout envelope 13 to create what is, in effect, a giant "flash bulb". A high energy, electrical pulse is supplied through lead 48 to ignite the metalic mesh 47 throughout envelope 13 to thereby initiate the explosion.
FIG. 8 discloses still another means for detonating the mixture in envelope 13. A plurality of electric blasting caps 50 are spaced on stringers 51 which are suspended within envelope 13 and are all connected to a firing lead 52. Caps 50 are fast-functioning, high strength instantaneous caps that detonate in less than half a millisecond after sufficient current flows through a bridge wire in each cap, e.g. DuPont "SSS" seismograph jet tapper electric blasting caps. Energy through firing lead 52 is delivered to each cap 50 at the same time so that all caps 50 detonate simultaneously to generate the maximum explosion within envelope 13.
FIG. 9 discloses still another means for detonating the mixture in envelope 13 which can be used in combination with any of the detonation means disclosed above. Metallic dust, flakes, small bits of wire, or the like 55, e.g. aluminum or organic dust, e.g. grain dust, is sprayed or otherwised distributed into the methane-oxygen mixture in envelope 13. One way of distributing this material is shown in FIG. 9 wherein the dust particles are sprayed out under pressure through inlet conduit 56. Outlet conduit 57, continuously sucks a portion of the dust and mixture from envelope 13 and circulates some through mixing blower 58 and back into envelope 13 through inlet conduit 56. For the above example, it is estimated that a 200-h.p. blower 58 will completely recirculate the contents of envelope 13 every hour.
Aluminum dust concentrations as low 0.025 ounce per cubic foot in air are known to explode violently. The dust may be ignited by a modest radio signal. If the aluminum dust is ignited by a remote radar signal, it would take the radar energy 0.3 microseconds to travel the diamter of a 268 foot sphere. It is estimated that the methane-oxygen detonation wave travels 6000 feet per second so where the aluminum dust particles are separate by 254 microns, the explosion within envelope 13 will take about 0.2 microseconds after the aluminum is ignited. This results in the entire methane-oxygen explosion taking place in less than one microsecond, making it as fast or faster than an equivalent T.N.T. explosion or nulcear explosion.
As stated above, dust particles can be dispersed into the envelope 13 and used in conjunction with any of the detonating means disclosed in FIGS. 2 through 8. In every instance the dust particles will enhance the explosion of the methane-oxygen mixture.
FIG. 10 discloses a modification of the present invention wherein the explosion is to be carried out above the earth's surface. Envelope 13 is first partially filled with a non-explosive methane-oxygen mixture as described above and then topped-out with the addition oxygen just prior to launch. The gas mixture within envelope 13 provides more than sufficient buoyancy for lifting the filled envelope 13 to an altitude above the earth's surface. Envelope 13 may be tethered in position by one or more tether lines 60 and is detonated by a firing lead within lines 60 or by radar or radio frequency energy transmitted by one or more antennae 61.
While methane is considered to be the preferably combustible gas in the present invention, there may be instances where other gas or combinations of gases may be considered. For example, hydrogen yields substantially less Btus per unit volume than methane when exploded but has a much lower mass per molecule. Since the speed of detonation increases as the mass of the molecules of the combustible gas decreases, the continuity of the detonation front through the explosive mixture should be improved by substituting an amount of hydrogen, e.g. 50% by volume, for a like volume of methane within envelope 13.
Also, while the gas-containing structure has been described as an inflatable, spherical envelope, it could take other shapes and configurations without departing from the present invention. For example, other inflatable or expandible shapes can be used such as dirigible-shaped envelopes, cylindrical envelopes, irregular-shaped envelopes, etc. Further, the structure may be an inflatable envelope in connection with a rigid framework, e.g. geodesic domes; a rigid base structure with only an inflatable covering or roof, e.g. domed staduim-like structures; or fully rigid, expendible structures, e.g. greenhouse-like structures. The primary consideration is to loosely contain the desired volume of explosive gas mixture so that when detonated, an explosion having the desired yield will result.
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WFETZER
Joined: 11 Jul 2002
Posts: 15
Location: Hopland, CA, Mendocino |
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Mon Aug 26, 2002 3:54 pm
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I thought it mighrt be of importance to note that the assignee on this patent is (APTI) ARCO Power Technologies, Inc.(the largest contractor hired by the govern. to construct the facility for HAARP in Alaska. APTI was sold to E-Systems which is owned by Raytheon.
Raytheon also purchased Huges Aircraft Company. So Raytheon owns not only this patent but patent #5,003,186 (Welsbach)as the assignee on that is Hughes Aircraft Company, Raytheon recently received a multi-million dollar contract to manufacture planes for the USAF. Whadddo ya know..... |
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Catnip57
Joined: 22 Apr 2001
Posts: 596
Location: Central Washington |
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Thu Aug 29, 2002 2:57 am
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Here's a bit of interesting information from page 146 of the book Angels Don't Play This Haarp by Jeane Manning and Dr. Nick Begich.
The concept of cyclotron resonance was applied to the research carried out by the U.S. Naval Medical Research Center. They were able to apply external fields in such a way as to affect the brain chemistry of rats. The same effects can be created in humans. The Navy research showed that they were able to affect the lithium ion occurring naturally in the brain, so as to create the same effect as if they had treated the animal with a chemical introduction of lithium. Stated another way, you could say that by harmonizing or resonation with the frequency of naturally-occurring chemicals, you could amplify their potency in the body of the animal, thereby creating the same chemical changes as would have occurred with a massive dose of the chemical being administered.
One military application of this knowledge would be to introduce to adversaries on the battlefield a minute amount of a chemical compound in their water supply, air supply or by other means and then (after they consume the contaminants) transmit the right frequencies toward them to activate the otherwise benign chemicals. It would cause debilitating effects. The chemical introductions would be below generally accepted levels for toxic effects, and yet toxic effects would occur. This is a way a country could slide around international agreements regarding chemical warfare.This technique has not been lost on the military: it is clearly understood and described in Air Force documents. These documents offer a clear example of the "electrical medicine" predicted by Dr. Patrick Flanagan in September, 1962 Unfortunately, the military's applications are being developed for the wrong purposes. The research base controlled by the United States government and others is being withheld from those engaged in human development and healing an unfortunate situation given the current state of the world and human health. |
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