Waves generated by pulsed electron beams

Torsten Neubert, K.J. Harker, P.M. Banks, E.G.D. Reeves, D.A. Gurnett

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review


During the Spacelab-2 flight of July, 1985, electron beams (1 keV, 100 mA) square-wave modulated at ELF and VLF were emitted from the space shuttle. The wave fields generated by the beam were monitored by a free-flying sub-satellite at distances up to 300 m perpendicular to the beam. The amplitude of the magnetic and electric fields were modulated by the spin of the satellite. This modulation allows the study of the wave polarization. Results for a 7 min duration beam sequence in which the beam was pulsed at 1.22 kHz are presented and compared with recent predictions for wave-fields stimulated by ideal helical electron beams propagating in a magnetized plasma. It is found that the predicted magnetic field amplitude of the first harmonic of the beam pulsing frequency (below the lower hybrid frequency) is in agreement with observations, however, the predicted and the observed polarizations are entirely different. For the higher harmonic components (above the lower hybrid frequency), theory predicts order of magnitude larger magnetic field amplitudes than observed. It is concluded that the theory does not adequately model the full distribution of the radiating current.
Original languageEnglish
Title of host publicationActive Experiments/Critical Ionization Velocity
PublisherPergamon Press
Publication date1990
ISBN (Print)0-08-040164-3
Publication statusPublished - 1990
Externally publishedYes
EventWorkshop of the Topical Meeting of the Interdisciplinary Commission of the COSPAR 27th Plenary Meeting: Active Experiments/Critical Ionization Velocity - Espoo, Finland
Duration: 18 Jul 198829 Jul 1988
Conference number: 27


WorkshopWorkshop of the Topical Meeting of the Interdisciplinary Commission of the COSPAR 27th Plenary Meeting
SeriesAdvances in Space Research


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