posted 08-21-2003 05:53 PM            

The HAARP Ionospheric Research facility will be a major Arctic facility for conducting upper atmospheric research. The facility will consist of two essential parts:
A high power transmitter and antenna array operating in the High Frequency (HF) range. When complete, the transmitter will be capable of producing up to 3.6 million Watts to an antenna system consisting of 180 crossed dipole antennas arranged as a rectangular, planar array.

A complete and extensive set of scientific instruments for observation of both the background auroral ionosphere and of the effects produced during active research using the transmitter system. Output from these instruments will be combined into an integrated data package which will be available world-wide in near real time over the internet.
During active ionospheric research, the signal generated by the transmitter system is delivered to the antenna array, transmitted in an upward direction, and is partially absorbed, at an altitude between 100 to 350 km (depending on operating frequency), in a small volume a few hundred meters thick and a few tens of kilometers in diameter over the site. The intensity of the HF signal in the ionosphere is less than 3 microwatts per cm2, tens of thousands of times less than the Sun's natural electromagnetic radiation reaching the earth and hundreds of times less than even the normal random variations in intensity of the Sun's natural ultraviolet (UV) energy which creates the ionosphere. The small effects that are produced, however, can be observed with the sensitive scientific instruments installed at the HAARP facility and these observations can provide new information about the dynamics of plasmas and new insight into the processes of solar-terrestrial interactions.

The complete HAARP antenna system is a technically known as a Planar Array, consisting of multiple horizontally polarized antenna elements. Each of these individual antenna elements, in turn, consists of two upper and two lower crossed dipole antennas mounted to a mast (or tower) above a wire mesh ground screen. The upper or lower crossed dipoles are selected depending on the desired operating frequency range. Because the design of these elements is mechanically complex, the drawings used in the following discussion have been simplified to include only half of the crossed dipoles making up each element.

What Is HAARP?
HAARP (High frequency Active Auroral Research Program) is to be a major Arctic facility for upper atmospheric and solar-terrestrial research. HAARP is being built on a DoD-owned site near Gakona, Alaska. Principal instruments include a high power, high-frequency (HF) phased array radio transmitter (known as the Ionospheric Research Instrument, or IRI), used to stimulate small, well-defined volumes of ionosphere, and an ultra-high frequency (UHF) incoherent scatter radar (ISR), used to measure electron densities, electron and ion temperatures, and Doppler velocities in the stimulated region and in the natural ionosphere. To further the scientific capabilities and usefulness of the IRI and ISR, HAARP is supporting the design and installation of the latest in modern geophysical research instruments, including an HF ionosonde, ELF and VLF receivers, magnetometers, riometers, a LIDAR (LIght Detection And Ranging) and optical and infrared spectrometers and cameras which will be used to observe the complex natural variations of Alaska's ionosphere as well as to detect artificial effects produced by the IRI.

Ionospheric research facilities have been in continuous use since the 1950's to investigate fundamental physical principles which govern the earth's ionosphere, so that present and future transmission technologies may take into account the complexities of the ionosphere. At the present time the US operates two ionospheric research sites, one in Puerto Rico, near the Arecibo Observatory, and the other known as HIPAS in Alaska near Fairbanks. Both of these employ active and passive radio instrumentation similar to that being built at HAARP. Interest in the ionosphere is not limited to the US: a five-country consortium operates the European Incoherent Scatter Radar site EISCAT, a premier world-class ionospheric research facility located in northern Norway near Tromsų. Facilities also are located at Jicamarca, Peru; near Moscow, Nizhny Novgorod "SURA" and Apatity, Russia; near Kharkov, Ukraine and in Dushanbe, Tadzhikistan. All of these installations have as their primary purpose the study of the ionosphere, and most employ the capability of stimulating to a varying degree small, localized regions of the ionosphere in order to study methodically, and in a detailed manner what nature produces randomly and regularly on a much larger scale. HAARP also will have such a capability, but what sets HAARP apart from existing facilities is the unusual combination of a research tool which provides electronic beam steering, wide frequency coverage and high effective radiated power collocated with a diverse suite of scientific observational instruments.

Who is Building HAARP?
Technical expertise and procurement services as required for the management, administration and evaluation of the program are being provided cooperatively by the Air Force. Air Force Research Laboratory and Navy Office of Naval Research and Naval Research Laboratory. Since HAARP consists of many individual items of scientific equipment, both large and small, there is a considerable list of commercial, academic and government organizations which are contributing to the building of the facility by developing scientific diagnostic instrumentation and by providing guidance in the specification, design and development of the IRI. Advanced Power Technologies, Inc. APTI, an employee-owned company, was awarded the contract to design and build the IRI, based on a proposal submitted in response to an RFP issued by the Office of Naval Research in 1992, and published in the Commerce Business Daily. Other organizations which have contributed to the program include the University of Alaska, University of Massachusetts, UCLA, MIT, Stanford University, Dartmouth University, Clemson University, Penn State University, University of Tulsa, University of Maryland, Cornell University, SRI International, Northwest Research Associates, Inc., and Geospace, Inc.

What is the Value of Ionospheric Research?
The ionosphere begins approximately 35 miles above the earth's surface and extends out beyond 500 miles. In contrast to the dense atmosphere close to the earth, which is composed almost entirely, of neutral gas, the thin ionosphere contains both neutral gas and a small number of charged particles known as ions and electrons. This ionized medium can distort, reflect and absorb radio signals, and thus can affect numerous civilian and military communications, navigation, surveillance and remote sensing systems in many varied ways. For example, the performance of a satellite-to-ground communication link is affected by the ionosphere through which the signals pass. AM broadcast programs, which in the daytime can be heard only within a few tens of miles from the station, at night sometimes can be heard hundreds of miles away, due to the change from poor daytime to good nighttime reflection from the ionosphere. A long-range HF communication link which uses multiple hops or reflections from the ionosphere and ground, often experiences amplitude fading caused by interference between signals which have traveled from the transmitter to the receiver by two or more different ionospheric paths.
Since the sun's radiation creates and maintains the ionosphere, sudden variations in this radiation such as those caused by solar flares can affect the performance of radio systems. Sometimes these natural changes are sufficient to induce large transient currents in electric power transmission grids, causing widespread power outages. Lightning is known to cause substantial heating and ionization density enhancement in the lower ionosphere, and there are indications that ground-based HF transmitters, including radars and strong radio stations, also modify the ionosphere and influence the performance of systems whose radio paths traverse the modified region. Perhaps the most famous example of the latter is the "Luxembourg" effect, first observed in 1933. In this case a weak Swiss radio station appeared to be modulated with signals from the powerful Luxembourg station, which was transmitting at a completely different frequency. Music from the Luxembourg station was picked up at the frequency of the Swiss station.

The continual growth in the number of civilian and military satellite systems whose performance depends on paths passing through the ionosphere, encourages not only good characterization and monitoring of the ionospheric state, but also an examination of what controlled local modification of the ionosphere, using ground HF transmitters, could do for and to these systems. Thus, while the HAARP facility is expected to provide significant advancements in understanding ionospheric science by stimulating and controlling plasma processes in a tiny localized region within the ionosphere, it also has the potential for significantly affecting the planning for future satellite communication and navigation systems through improvements in reliability and economics.

Why is the DoD Involved?
The Department of Defense DoD conducts Arctic research to ensure the development of the knowledge, understanding and capability to meet national defense needs in the Arctic. Interest in ionospheric research at HAARP stems both from the large number of communication, surveillance and navigation systems that have radio paths which pass through the ionosphere, and from the unexplored potential of technological innovations which suggest applications such as detecting underground objects, communicating to great depths in the sea or earth, and generating infrared and optical emissions. Expanding our knowledge about the interactions of signals passing through or reflecting from the ionosphere can help to solve future problems in the development of DoD systems, and could as well enhance the utilization of commercial systems which rely on the expedient transfer of real-time communications.

Why Gakona, Alaska?
During HAARP's environmental impact study, Gakona was identified as one of two DoD-owned, Alaskan locations which satisfied the site selection criteria of being within the auroral zone, near a major highway for year-round access, away from densely settled areas, of sufficient size to allow for equipment siting and separation space, on relatively flat terrain, of realistic and reasonable construction and operation costs as well as minimal environmental impacts. On October 18, 1993 following the July 15, 1993 issuance of the Air Force's Environmental Impact Statement which evaluated potential environmental effects of constructing and operating the HAARP facility, a Record of Decision ROD signed by the Deputy Assistant Secretary of the Air Force for Installations selected Gakona as the location for the HAARP facility.