Nonlinear evolution of the auroral electron beam

Journal Article · Sat Apr 01 00:00:00 EST 1989 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JA094iA04p03631· OSTI ID:5915505

Maggs, J E ^[1]

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1. Univ. of California, Los Angeles (USA)

The nonlinear spatial evolution of the auroral electron beam and beam-generated electrostatic whistler noise is followed from source to atmosphere. Changes in beam parameters are determined by using the equations of conservation of total particle and wave energy and momentum flux density. Wave power fluxes are calculated by numerically integrating the wave kinetic equation. Levels of beam generated noise are quantified by using thermal levels of Cerenkov radiation as a source. Wave refraction and source geometry as well as beam recoil and thermalization influence beam generated power flux spectra. Beam parameters evolve on ionospheric scale lengths, and their positive slope feature in velocity space is maintained over thousands of kilometers of altitude even though they can generate wave energy density fluxes sufficient to modify the ionospheric density profile. For a beam source at 7,000 km altitude, peak fluxes of electrostatic whistler noise as high as 10{sup {minus}10} W/m{sup 2} Hz can be generated in the altitude region between 3,000 and 5,000 km. Beams with densities large enough to be unstable at the source altitude generate sufficient wave noise at the plasma frequency to disrupt the source structure.

• OSTI ID: 5915505
• Journal Information: Journal of Geophysical Research; (USA), Vol. 94:A4; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAE
ELECTRON BEAMS
CALCULATION METHODS
CHERENKOV RADIATION
ELECTRON DENSITY
ELECTRON PRECIPITATION
GEOMAGNETIC FIELD
IONOSPHERE
LANGMUIR FREQUENCY
MATHEMATICAL MODELS
NONLINEAR PROBLEMS
WAVE EQUATIONS
WHISTLERS
BEAMS
CHARGED-PARTICLE PRECIPITATION
DIFFERENTIAL EQUATIONS
EARTH ATMOSPHERE
ELECTROMAGNETIC RADIATION
EQUATIONS
LEPTON BEAMS
MAGNETIC FIELDS
NOISE
PARTIAL DIFFERENTIAL EQUATIONS
PARTICLE BEAMS
PLANETARY IONOSPHERES
RADIATIONS
RADIO NOISE
RADIOWAVE RADIATION
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena