The HAARP in operation

The High Frequency Active Auroral Research Program (HAARP) is an ionospheric research program jointly funded by the U.S. Air Force, the U.S. Navy, the University of Alaska, and the Defense Advanced Research Projects Agency (DARPA). Designed and built by BAE Advanced Technologies (BAEAT), its purpose is to analyze the ionosphere and investigate the potential for developing ionospheric enhancement technology for radio communications and surveillance. The HAARP program operates a major sub-arctic facility, named the HAARP Research Station, on an Air Force-owned site near Gakona, Alaska.

The most prominent instrument at the HAARP Station is the Ionospheric Research Instrument (IRI), a high-power radio frequency transmitterfacility operating in the high frequency (HF) band. The IRI is used to temporarily excite a limited area of the Ionosphere. Other instruments, such as a VHF and a UHF radar, a fluxgate magnetometer, a digisonde (an ionospheric sounding device), and an induction magnetometer, are used to study the physical processes that occur in the excited region.

Work on the HAARP Station began in 1993. The current working IRI was completed in 2007, and its prime contractor was BAE Systems Advanced Technologies. As of 2008, HAARP had incurred around $250 million in tax-funded construction and operating costs. It was reported to be temporarily shut down in May 2013, awaiting a change of contractors. In May 2014, it was announced that the HAARP program would be permanently shut down later in the year.

HAARP was a target of conspiracy theorists, who claimed that it was capable of modifying weather, disabling satellites and exerting mind control over people, and that it was being used as a weapon against terrorists. Such theorists blamed the program for causing earthquakes, droughts, storms and floods, diseases such as Gulf War Syndrome and Chronic Fatigue Syndrome, the 1996 crash of TWA Flight 800, and the 2003 destruction of the space shuttle Columbia. Commentators and scientists say that proponents of these theories are "uninformed", because most theories put forward fall well outside the abilities of the facility and often outside the scope of natural science.

History

The HAARP program began in 1990. A powerful U.S. senator from Alaska, Republican Ted Stevens, helped win approval for the facility, whose construction began in 1993.

In early May 2013, HAARP was temporarily shut down, awaiting a change between contractors who operated the facility. In July 2013, HAARP program manager James Keeney said, "Defense Advanced Research Projects Agency (DARPA) is expected on site as a client to finish up some research in fall 2013 and winter 2014." The temporary shutdown was described as being due to "a contractor regime change." Ahtna, Incorporated, the Alaska Native corporation serving the region of Alaska where the HAARP site is located, was reportedly in talks to take over the facility administration contract from Marsh Creek, LLC.

In May 2014, the Air Force announced that the HAARP program would be shut down later in 2014.

 Instrumentation and operation

The main instrument at HAARP Station is the Ionospheric Research Instrument (IRI). This is a high power, high-frequency phased array radio transmitter with a set of 180 antennas, disposed in an array of 12x15 units that occupy a rectangle of about 33 acres (13 hectares). The IRI is used to temporarily energize a small portion of the ionosphere. The study of these disturbed volumes yields important information for understanding natural ionospheric processes.

During active ionospheric research, the signal generated by the transmitter system is delivered to the antenna array and transmitted in an upward direction. At an altitude between 70 to 350 km (43 to 217 mi) (depending on operating frequency), the signal is partially absorbed in a small volume several tens of kilometers in diameter and a few meters thick over the IRI. The intensity of the HFsignal in the ionosphere is less than 3 µW/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 Station, and these observations can provide information about the dynamics of plasmas and insight into the processes of solar-terrestrial interactions.

Each antenna element consists of a crossed dipole that can be polarized for linear, ordinary mode (O-mode), or extraordinary mode (X-mode) transmission and reception. Each part of the two section crossed dipoles are individually fed from a specially designed, custom built transmitter, that operates at very low distortion levels. The Effective Radiated Power (ERP) of the IRI is limited by more than a factor of 10 at its lower operating frequencies. Much of this is due to higher antenna losses and a less efficient antenna pattern.

The IRI can transmit between 2.7 and 10 MHz, a frequency range that lies above the AM radio broadcast band and well below Citizens' Band frequency allocations. The HAARP Station is licensed to transmit only in certain segments of this frequency range, however. When the IRI is transmitting, the bandwidth of the transmitted signal is 100 kHz or less. The IRI can transmit in continuous waves (CW) or in pulses as short as 10 microseconds (µs). CW transmission is generally used for ionospheric modification, while transmission in short pulses frequently repeated is used as a radar system. Researchers can run experiments that use both modes of transmission, first modifying the ionosphere for a predetermined amount of time, then measuring the decay of modification effects with pulsed transmissions.

There are other geophysical instruments for research at the Station. Some of them are:

• A fluxgate magnetometer built by the University of Alaska Fairbanks Geophysical Institute, available to chart variations in the Earth's magnetic field. Rapid and sharp changes of it may indicate a geomagnetic storm.
• A digisonde that provides ionospheric profiles, allowing scientists to choose appropriate frequencies for IRI operation. The HAARP makes current and historic digisonde information available online.
• An induction magnetometer, provided by the University of Tokyo, that measures the changing geomagnetic field in the Ultra Low Frequency (ULF) range of 0–5 Hz.

The Station is powered by a set of five (5) 2500 kilowatt generators being driven by EMD 20-645-E4 diesel locomotive engines.

Source of information:

http://en.wikipedia.org/wiki/High_Frequency_Active_Auroral_Research_Program