Electron cyclotron wave generation by relativistic electrons

Journal Article · Sat Jan 01 04:00:00 EST 1994 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/93JA02319· OSTI ID:6720665

Wong, H K ^[1]; Goldstein, M L ^[2]

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1. Southwest Research Institute, San Antonio, TX (United States)
2. NASA/Goddard Space Flight Center, Greenbelt, MD (United States)

The authors show that an energetic electron distribution which has a temperature anisotropy (T[sub [perpendicular]b] > T[sub [parallel]b]), or which is gyrating about a DC magnetic field, can generate electron cyclotron waves with frequencies below the electron cyclotron frequency. Relativistic effects are included in solving the dispersion equation and are shown to be quantitatively important. The basic idea of the mechanism is the coupling of the beam mode to slow waves. The unstable electron cyclotron waves are predominantly electromagnetic and right-hand polarized. For a low-density plasma in which the electron plasma frequency is less than the electron cyclotron frequency, the excited waves can have frequencies above or below the electron plasma frequency, depending upon the parameters of the energetic electron distribution. This instability may account for observed Z mode waves in the polar magnetosphere of the Earth and other planets. 26 refs., 6 figs.

• OSTI ID: 6720665
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 99:A1; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CYCLOTRON RESONANCE
DISTRIBUTION FUNCTIONS
ELECTRON CYCLOTRON-RESONANCE
ELECTRONS
ELEMENTARY PARTICLES
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EXCITATION
FERMIONS
FUNCTIONS
INSTABILITY
LEPTONS
PLASMA WAVES
RELATIVISTIC RANGE
RESONANCE