Alaska’s super-power High-Frequency Active Auroral Research Program (HAARP) transmitters in Gakona, Alaska, will fire up again for the spring research campaign April 6 – 14. University of Alaska Fairbanks (UAF) Space Physics Group researcher and HAARP Chief Scientist Chris Fallen, KL3WX, told ARRL that more than 40 hours of “externally funded” experiments are in the queue.
“Scientists from US universities and government labs will explore the physics of scintillations, magnetic field-aligned plasma irregularities, artificial and natural atmospheric airglow, stimulated electromagnetic emissions, plasma waves, and radio-enhanced ionization,” Fallen said. “The HAARP transmitter is still at 80% net power, but by summer we expect to have the final ‘column’ of transmitters restored, bringing the array back to 100%.”
For his part, Fallen said he still has some time remaining on his National Science Foundation (NSF) grant to study artificial airglow, but added that this is “a tough time of year in a tough year of the solar cycle” for such experiments. “It will not be dark enough in Gakona to observe artificial airglow emissions until 10 PM at the beginning of the campaign and 10:30 PM at the end of the campaign, due to the rapidly lengthening days in the Land of Midnight Sun.”
Fallen said that due to weakening solar activity, the critical frequency of the ionosphere’s F2 layer (foF2) is relatively low during the day, peaking at a little more than 4 MHz above Gakona in the late afternoon, and falling rapidly in the evening. “This limits the time available for experiments, since airglow is usually only created when the HAARP transmission frequency is near or below foF2,” Fallen explained. “The lower limit of the HAARP transmitter is approximately 2.7 MHz, and so we can only expect perhaps 30 minutes or less of usable airglow experiment time each day.”
Read More: ARRL.org