The High-frequency Active Auroral Research Program (HAARP)
https://en.wikipedia.org/wiki/High-frequency_Active_Auroral_Research_Program


he High-frequency Active Auroral Research Program (HAARP) is a University of Alaska Fairbanks program which researches the ionosphere – the highest, ionized part of Earth's atmosphere. The most prominent instrument at HAARP is the Ionospheric Research Instrument (IRI), a high-power radio frequency transmitter facility 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 facility began in 1993. Initially HAARP was jointly funded by the U.S. Air Force, the U.S. Navy, the University of Alaska Fairbanks, and the Defense Advanced Research Projects Agency (DARPA). It was designed and built by BAE Advanced Technologies. Its original purpose was to analyze the ionosphere and investigate the potential for developing ionospheric enhancement technology for radio communications and surveillance. Since 2015 it has been operated by the University of Alaska Fairbanks.

The current working IRI was completed in 2007; its prime contractor was Systems Advanced Technologies (BAE). As of 2008, HAARP had incurred around $250 million in tax-funded construction and operating costs. In May 2014, it was announced that the HAARP program would be permanently shut down later in the year. After discussions between the parties, ownership of the facility was transferred to the University of Alaska Fairbanks in August 2015.

Project overview

HAARP began operating in 1999 as a 6 × 8 (= 48) antenna array at 0.96 MW, expanding in 2007 to a 12 × 15 (=180) array of 180 antennas with 360 radio transmitters at 9.6 MW. The HAARP project directs a 3.6 MW signal, in the 2.8–10 MHz region of the HF band, into the ionosphere. The signal may be pulsed or continuous. Effects of the transmission and any recovery period can be examined using associated instrumentation, including VHF and UHF radars, HF receivers, and optical cameras. According to the HAARP team, this will advance the study of basic natural processes that occur in the ionosphere under the natural but much stronger influence of solar interaction. HAARP also enables studies of how the natural ionosphere affects radio signals.

The insights gleaned at HAARP will enable scientists to develop methods to mitigate these effects to improve the reliability or performance of communication and navigation systems which would have a wide range of both civilian and military uses, such as an increased accuracy of GPS navigation and advances in underwater and underground research and applications. This may lead, among other things, to improved methods for submarine communication or an ability to remotely sense and map the mineral content of the terrestrial subsurface, and perhaps underground complexes, of regions or countries. The current facility lacks range to be used in regions like the oil-rich Middle East, according to one of the researchers involved, but the technology could be put on a mobile platform.

Research

HAARP's main goal is basic science research in the uppermost portion of the atmosphere, termed the ionosphere. Essentially a transition between the atmosphere and the magnetosphere, the ionosphere is where the atmosphere is thin enough that the Sun's X-rays and UV rays can reach it, but thick enough that there are enough molecules present to absorb those rays. Consequently, the ionosphere consists of a rapid increase in density of free electrons, beginning at ~70 km, reaching a peak at ~300 km, and then falling off again as the atmosphere disappears entirely by ~1,000 km. Various aspects of HAARP can study all of the main layers of the ionosphere.

The profile of the ionosphere is highly variable, changing constantly on timescales of minutes, hours, days, seasons, and years. This profile becomes even more complex near Earth's magnetic poles, where the nearly vertical alignment and intensity of Earth's magnetic field can cause physical effects like the aurora.

The ionosphere is traditionally very difficult to measure. Balloons cannot reach it because the air is too thin, but satellites cannot orbit there because the air is too thick. Hence, most experiments on the ionosphere give only small pieces of information. HAARP approaches the study of the ionosphere by following in the footsteps of an ionospheric heater called EISCAT near Tromsø, Norway. There, scientists pioneered exploration of the ionosphere by perturbing it with radio waves in the 2–10 MHz range, and studying how the ionosphere reacts. HAARP performs the same functions but with more power and a more flexible and agile HF beam.