What does HIPAS mean in Unclassified?

hipas

The HIPAS (HIgh Power Auroral Stimulation) Observatory was a research facility, built to study the ionosphere and its influence on radio communications. It was located 25 miles east of Fairbanks, Alaska in the Fairbanks North Star Borough area.It was operated by the UCLA plasma physics laboratory from 1986 through 2007. A unique capability at that time, it could radiate 70 MW ERP at either 2.85 MHz or 4.53 MHz. These frequencies are close to a multiple of 2 and 3 of the electron gyro-frequency at ionospheric altitudes. Sending a pulse of HF-radio waves upward could accelerate the electrons in the ionosphere. Somewhat like waves on the ocean, the character of the ionosphere could be inferred from the backscatter signal. Other experiments attempted to combine RF and visible excitation where the latter probed metal ions such as sodium.

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