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New aspects of whistler waves driven by an electron beam studied by a 3-D electromagnetic codeWe have restudied electron beam driven whistler waves with a 3-D electromagnetic particle code. The simulation results show electromagnetic whistler wave emissions and electrostatic beam modes like those observed in the Spacelab 2 electron beam experiment. It has been suggested in the past that the spatial bunching of beam electrons associated with the beam mode may directly generate whistler waves. However, the simulation results indicate several inconsistencies with this picture: (1) whistler waves continue to be generated even after the beam mode space charge modulation looses its coherence, (2) the parallel (to the background magnetic field) wavelength of the whistler wave is longer than that of the beam instability, and (3) the parallel phase velocity of the whistler wave is smaller than that of the beam mode. The complex structure of the whistler waves in the vicinity of the beam suggest that the transverse motion (gyration) of the beam and background electrons is also involved in the generation of whistler waves.
Document ID
19950043533
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Nishikawa, Ken-Ichi (University of Iowa IA, United States)
Buneman, Oscar (Stanford University Stanford, CA, United States)
Neubert, Torsten (University of Michigan, Ann Arbor, MI United States)
Date Acquired
August 16, 2013
Publication Date
June 1, 1994
Publication Information
Publication: Geophysical Research Letters
Volume: 21
Issue: 11
ISSN: 0094-8276
Subject Category
GEOPHYSICS
Funding Number(s)
CONTRACT_GRANT: NSF ATM-91-21116
CONTRACT_GRANT: NAS8-38772
CONTRACT_GRANT: NAGW-2350
CONTRACT_GRANT: NSF ATM-91-19814
CONTRACT_GRANT: NSF ATM-91-06639
Distribution Limits
Public
Copyright
Other