HAARP installation
HAARP aerials - a wide, panoramic photo (87K .jpg)

HAARP

Background

The HAARP Interactive Ionospheric Research Observatory will be a major Arctic facility for upper atmospheric and solar-terrestrial research. Among the instruments to be installed at the site are a high power, high-frequency (HF) phased array radio transmitter, an ultra-high frequency (UHF) incoherent scatter radar (ISR), numerous sophisticated geophysical research instruments capable of observing and monitoring the complex auroral ionosphere, and site infrastructure to support research activities.

The site is being developed in a gradual but determined manner such that scientific results can be obtained early in the program and increase in quality and quantity as development progresses. The following sections summarize the current state of development for each of the major parts of the HAARP facility and give some idea of the scientific capability currently available.

The High Frequency Transmitter and Antenna Array

The HAARP HF transmitter/antenna consists of 48 antenna elements arranged as a rectangular array of 8 columns by 6 rows.During 1997 and 1998, the HF antenna array was upgraded so that all of the 48 elements are functional. This subset of the final 180 element antenna system is called the Filled Developmental Prototype (FDP). During the upgrade, the original antenna matching unit design was modified and all of the original units replaced to improve the overall performance of the system.

As a result of this work, successfully completed late in 1998, the HF transmitter at HAARP is now capable of operating at the 960 kW level. Engineering testing of the transmitter and antenna system during December 1998 and in February 1999 has confirmed its excellent performance, versatility and reliability in support of interactive ionospheric research.

Between December, 1994 and February 1999, twelve engineering tests have been conducted at the facility, each lasting from a few days to two weeks. The purpose of these tests was to evaluate the engineering design against contract specifications and to confirm that all requirements of the Environmental Impact Process (EIP), Record of Decision with respect to absolute public safety and interference mitigation can and will be met with the completed design. An initial research campaign was conducted during March, 1997. The first research campaign using the full 48 element FDP was conducted between March 8-29, 1999.

Additional tests are planned during 1999 to continue the ongoing verification of the electromagnetic safety of the facility by measurement of the field strength at locations both on and off the site. Measurements made in December 1998 and March 1999 verify that the field strengths at all public access points surrounding the facility are well below the adopted safety standards.

The first HAARP research campaign was conducted in March 1997. Results from this campaign were reported at the American Geophysical Union Conference at San Francisco, CA in December 1997 and at the URSI conference at Boulder, CO. in January 1998. The first research campaign using the upgraded 48 element HF transmitter was conducted during March 1999. Research topics for this effort included evaluation of various techniques for generation of ULF/ELF/VLF signals, generation of field aligned irregularities (FAI), observation of ionospheric emissions in the 630 nm range, scatter communications from FAI, transionospheric propagation using the NASA WIND satellite as a detector, and observation of ionospheric scintillations on VHF/UHF satellite signals. Initial results from this research effort indicate the campaign has been highly successful. It is expected that results will be published in peer-reviewed journals.

The Incoherent Scatter Radar

The HAARP program is cooperating with the National Science Foundation (NSF) in development of the specification for an Arctic Incoherent Scatter Radar (ISR). The goal is to agree on a single design that can be used for the development and construction of ISRs for use in the NSF High Latitude Facility as well as at the HAARP site. The ISR working group has met several times and a unified set of performance requirements was presented at the most recent RF Ionospheric Interactions Workshop, held April 27-30, 1997 in Santa Fe, New Mexico.

HAARP Scientific and Monitoring Instruments

The HAARP observatory has numerous scientific instruments operating full time at the Gakona site. These instruments provide continuous monitoring of the auroral geophysical background and are also used during science campaigns to assist in determining optimum operating parameters and in observing and diagnosing results.

The scientific instruments currently operating are:

  • A flux gate magnetometer
  • A whole sky VHF (30 MHz) riometer
  • An imaging riometer
  • A digital ionosonde
  • An optical imager
  • A GPS based, total electron content (TEC) monitor
  • VHF/UHF Scintillation monitors
  • A spectrum monitor

Data from each of these instruments are being archived by their principle investigators. Geophysical information from these instruments is readily available in near real time and in archived form from links in the data section of the HAARP home page.

The existing site access road was extended northward along the BLM trail during the spring of 1998. One additional gravel pad was placed near the end of this extension. The new gravel pad provides space for an optical shelter which houses additional scientific instruments including the ionosonde, total electron count monitors, and optical telescopes and imagers. This shelter, in addition to providing much needed internal work and instrument space, is equipped with four specially constructed optical domes that permit mounting sensitive telescopes and an all-sky camera for detailed study of the auroral ionosphere.

Site Infrastructure and Support

Six 2.5 MW diesel generators were acquired under the previous, OTH-B program that was to have used the current HAARP site in the 1980s. When that program was cancelled, the generators were transferred to HAARP and are being held in storage. Beginning late in 1997, one of these generators was refurbished by Pacific Detroit Diesel-Allison in Anchorage, trucked to Gakona and installed in the power building located near the entrance to the site. Installation of this generator was completed during May 1998. The generator has been used to test the completed 48 element HF transmitter during 1998 and early 1999 and has operated flawlessly.

Additional tests were conducted on the aircraft alert radar during 1998 and on an additional radar candidate during February 1999. Although the original radar continues to function as required, alternative equipment is being evaluated whenever possible for potential use to ensure that the requirements of the EIP Record of Decision are met.