Accession Number : ADA131868

Title :   A Model for Chorus Associated Electrostatic Bursts.

Descriptive Note : Progress rept.,

Corporate Author : IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY

Personal Author(s) : Grabbe,Crockett L

PDF Url : ADA131868

Report Date : 30 Jun 1983

Pagination or Media Count : 31

Abstract : The linear theory of the generation of electrostatic bursts of noise by electrons trapped in chorus wave packets is developed for a finite temperature electron beam and a Maxwellian electron and ion background. The growth rates determined qualitatively in good agreement with those obtained by previous authors from a more idealized model. Two connected instability mechanisms seem to be occurring: a beam plasma (electron-ion two-stream) instability commonly associated with intensification of the chorus power levels, and a transitional or borderline resistive medium instability commonly associated with chorus hooks. The physical reasons for the two mechanisms is discussed. In the second case electron beams are difficult to identify in the particle data. An expression is obtained for the maximum growth rate in terms of the ratios of the beam and electron thermal velocities to the beam velocity, and of the beam density to plasma density. It is anticipated that this may allow the observed peak in the electrostatic noise spectrum to be used as a diagnostic for the beam characteristics. (Author)

Descriptors :   *Electron beams, *Electrostatics, *Wave packets, *Trapping(Charged particles), *Maxwells equations, *Plasmas(Physics), Distribution functions, Thermal instability, Ion beams, Charts, Geophysics

Subject Categories : Statistics and Probability
      Particle Accelerators
      Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE