Wave-particle interactions induced by SEPAC on Spacelab 1: Wave observations

Space experiments with particle accelerators (SEPAC) flew on Spacelab 1 in November and December 1983 SEPAC included an accelerator which emitted electrons into the ionospheric plasma with energies up to 5 keV and currents up to 300 mA. The SEPAC equipment also included an energetic plasma generator, a neutral gas generator, and an extensive array of diagnostics. The diagnostics included plasma wave detectors, an energetic electron analyzer, a photometer, a high sensitivity television camera, a Langmuir probe and a pressure gauge. Twenty-eight experiments were performed during the mission to investigate beam-plasma interactions, electron beam dynamics, plasma beam propagation, and vehicle charging. The wave-particle interactions were monitored by the plasma wave instrumentation, by the energetic electron detector and by the optical detectors. All show evidence of wave-particle interactions, which will be described in this paper.