Investigation of Stimulated Electromagnetic Emission SEE during second electron gyro-harmonic heating

Abstract

Features in the Stimulated Electromagnetic Emission (SEE) spectrum during heating near the second electron gyro-harmonic frequency have recently attracted significant attention due to their possible connection to artificial airglow and artificially generated ionization layers. Experimentally, three new phenomenologically related spectral features within 1 kHz of the heater frequency have been recently discovered: (1) discrete narrowband spectral structures ordered by ion gyro-frequency, (2) broadband features with power spectral density maximum near 500 Hz and (3) the broadband features with embedded ion gyro-harmonic structures.