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Title: Theory for chorus generation by energetic electrons during substorms

Abstract

Previous observations during magnetospheric substorm reveal the existence of relatively narrow band electromagnetic emission occurring slightly above and below one half of the electron cyclotron frequency in the equatorial magnetosphere beyond the plasmapause. Between these two bands of emission there exists a gap of much lower emission intensity. In this paper an interpretation is presented for these chorus observations wherein the lower emission band is represented by whistler noise and the upper emission band is described by the lowest harmonic of the ordinary mode. These emissions are assumed to be locally generated at the observation point. Both emission bands are excited by power law-distributed energetic electrons with a variable spectral index and a weak loss cone feature. The form of these energetic electrons is similar to the forms observed simultaneously with the chorus emissions. The calculated growth rates show a frequency distribution similar to that of the measured emissions. In addition, the same energetic electron distribution can also produce the electrostatic gyroharmonic emissions often seen by observers in conjunction with chorus emissions during substorms.

Authors:
Publication Date:
Research Org.:
Laboratory for Planetary Atmospheres, NASA Goddard Space Flight Center Greenbelt, Maryland 20771
OSTI Identifier:
6617077
Resource Type:
Journal Article
Journal Name:
J. Geophys. Res.; (United States)
Additional Journal Information:
Journal Volume: 83:A8
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; MAGNETIC BAYS; WHISTLERS; CYCLOTRON FREQUENCY; ELECTRON PRECIPITATION; FREQUENCY DEPENDENCE; HARMONICS; PLASMA WAVES; CHARGED-PARTICLE PRECIPITATION; ELECTROMAGNETIC RADIATION; NOISE; OSCILLATIONS; RADIATIONS; RADIO NOISE; RADIOWAVE RADIATION; 640203* - Atmospheric Physics- Magnetospheric Phenomena- (-1987)

Citation Formats

Curtis, S A. Theory for chorus generation by energetic electrons during substorms. United States: N. p., 1978. Web. doi:10.1029/JA083iA08p03841.
Curtis, S A. Theory for chorus generation by energetic electrons during substorms. United States. doi:10.1029/JA083iA08p03841.
Curtis, S A. Tue . "Theory for chorus generation by energetic electrons during substorms". United States. doi:10.1029/JA083iA08p03841.
@article{osti_6617077,
title = {Theory for chorus generation by energetic electrons during substorms},
author = {Curtis, S A},
abstractNote = {Previous observations during magnetospheric substorm reveal the existence of relatively narrow band electromagnetic emission occurring slightly above and below one half of the electron cyclotron frequency in the equatorial magnetosphere beyond the plasmapause. Between these two bands of emission there exists a gap of much lower emission intensity. In this paper an interpretation is presented for these chorus observations wherein the lower emission band is represented by whistler noise and the upper emission band is described by the lowest harmonic of the ordinary mode. These emissions are assumed to be locally generated at the observation point. Both emission bands are excited by power law-distributed energetic electrons with a variable spectral index and a weak loss cone feature. The form of these energetic electrons is similar to the forms observed simultaneously with the chorus emissions. The calculated growth rates show a frequency distribution similar to that of the measured emissions. In addition, the same energetic electron distribution can also produce the electrostatic gyroharmonic emissions often seen by observers in conjunction with chorus emissions during substorms.},
doi = {10.1029/JA083iA08p03841},
journal = {J. Geophys. Res.; (United States)},
number = ,
volume = 83:A8,
place = {United States},
year = {1978},
month = {8}
}