Electron Gyro-Harmonics Generated by Spaceborne Artificial Electron Beam,
LABORATOIRE DE PHYSIQUE ET CHIMIE DE L'ENVIRONNEMENT ORLEANS (FRANCE)
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Results on high-frequency waves generated by the PICPAB Phenomena Induced by Charged Particle Beams experiment flown on the Spacelab-1 shuttle mission are presented. Then we propose an interpretation for the wave generation mechanism associated with such an experiment. This experiment comprised both electron and ion accelerators of a few keV energy installed on board the space shuttle and associated with nearby diagnostic instruments such as plasma and wave analysers. First, the observations are compared to previous results obtained in similar conditions and they are discussed in the frame of various beam plasma interactions models. The main features are electron cyclotron harmonics which appear modulated in amplitude with maxima occuring near the harmonics of the upper hybrid resonance. An interaction between the return flux electrons and the ambient plasma is thought to have generated the first cyclotron harmonics close to fuh, and, after non-linear saturation and trapping processes, the entire spectrum. By mean of a non-linear single-wave model developed analytically and solved numerically, we finally recover most of the experimental features.
- Atmospheric Physics