Competing processes of whistler and electrostatic instabilities in the magnetosphere

Journal Article · Sat Aug 01 04:00:00 EDT 1987 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA092iA08p08649· OSTI ID:6017380

Omura, Y; Matsumoto, H

Competing processes of whistler mode and electrostatic mode instabilities induced by an electron beam are studied by a linear growth rate analysis and by an electromagnetic particle simulation. In addition to a background cold plasma we assumed an electron beam drifting along a static magnetic field. We studied excitation of whistler and electrostatic mode waves in the direction of the static magnetic field. We first calculated linear growth rates for the whistler mode and electrostatic mode instabilities, assuming various possible parameters in the equatorial magnetosphere. We found that the growth rate for the electrostatic instability is always larger than that of the whistler mode instability. A short simulation run with a monoenergetic electron beam demonstrates that a monoenergetic beam can hardly give energy to whistler mode waves as a result of competition with faster growing electrostatic waves, because the beam electrons are trapped and diffused by the electrostatic waves, and hence the growth rates for whistler mode waves become very small. A long simulation run starting with a warm electron beam demonstrates that whistler mode waves are excited in spite of the small growth rates and the coexisting quasi-linear electrostatic diffusion process.

• Research Organization: Department of Electrical Engineering, Kyoto University, Kyoto, Japan
• OSTI ID: 6017380
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 92:A8; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BEAMS
COLD PLASMA
DIFFUSION
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTROMAGNETIC RADIATION
ELECTRON BEAMS
ELECTRON TEMPERATURE
INSTABILITY
LEPTON BEAMS
MATHEMATICAL MODELS
NOISE
PARTICLE BEAMS
PLASMA
PLASMA INSTABILITY
RADIATIONS
RADIO NOISE
RADIOWAVE RADIATION
VELOCITY
WAVE PROPAGATION
WHISTLERS