Determining Energy Distributions of HF-Accelerated Electrons at HAARP
Technical Report,15 Aug 2012,14 Nov 2015
University of Alaska Fairbanks Fairbanks
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The main project objective was to determine energy distribution of ionosphere electrons accelerated by powerful high-frequency HF radio waves transmitted from the High-frequency Active Auroral Research Program HAARP transmitter in Alaska. For a given fixed HF-plasma interaction altitude, results from this research show that a dual source of 20 eV electrons applied at 150 km and 200 km altitudes is sufficient to reproduce the substantial artificial airglow and plasma density enhancements created and observed at HAARP during March, 2009. A new discovery resulting from this project is that significant artificial 427.8 nm wavelength airglow can result from thermal heating of the ionosphere plasma and hence is not necessarily an indicator of energetic electrons accelerated to energies exceeding 20 eV as previously assumed. There are several unresolved science issues regarding the spatiotemporal evolution of HF-enhanced airglow and ionization structures. In particular, the apparent sensitive dependence of the artificial airglow and plasma structures on pump frequency relative to electron gyroharmonic frequencies cannot yet be explained, nor can the discrepancy between measurements and calculated dependence of relative intensities of airglow emission lines on altitude.