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Electromagnetic cyclotron-loss-cone instability associated with weakly relativistic electrons

Published online by Cambridge University Press:  13 March 2009

H. K. Wong
Affiliation:
Institute for Physical Science and Technology, University of Maryland
C. S. Wu
Affiliation:
Institute for Physical Science and Technology, University of Maryland
F. J. Ke
Affiliation:
Institute for Physical Science and Technology, University of Maryland
R. S. Schneider
Affiliation:
Instituto de Física, Universidade Federal do Rio Grande do Sul, 90000 Porto Alegre, RS, Brazil
L. F. Ziebell
Affiliation:
Instituto de Física, Universidade Federal do Rio Grande do Sul, 90000 Porto Alegre, RS, Brazil

Abstract

The amplification of fast extraordinary mode waves with frequencies very close to the electron cyclotron frequency is investigated for a plasma which consists of a weakly relativistic electron component with a loss-cone type distribution and a cold background electron component. The basic mechanism of the amplification is attributed to a relativistic cyclotron resonance between the wave and the energetic electrons. The method employed in the present analysis enables us to solve the dispersion relation in a self-consistent manner for arbitrary ratio of the densities of the energetic and background electrons. It is found that the maximum growth rates occur at certain values of ω2pe2e and the angular dependence of the growth rate is sensitive to the ratios ω2pe2e and ne/nb. Here ωpe and Ωe are the electron plasma frequency and the electron cyclotron frequency, respectively, and ne and nb denote the number densities of the energetic and background electrons, respectively.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1982

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