Accession Number : AD0487922

Title :   MICROPULSATIONS AND THE OUTER RADIATION ZONE.

Descriptive Note : Rept. for Jun 65-Feb 66,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS

Personal Author(s) : Cornwall,John M.

Report Date : JUL 1966

Pagination or Media Count : 41

Abstract : Recently the present author and others have suggested that Pcl micropulsations (hydromagnetic waves of frequency 0.1 - 5 cps) are generated in the outer radiation zone (L>4) by low-energy protons via a cyclotron instability. Several points are discussed in this report; the first concerns the interpretation of ground-based experimental data in the light of the above model. A simple formula is given for the highest emitted frequency on a given field line, which formula is in good agreement with the data. Secondly, it is observed that the combined processes of cyclotron instabilities and pitch-angle scattering give rise to upper limits on both the energy density of trapped particles and of Pcl wave fields. This saturation effect may account for the remarkable stability of the low-energy proton population against fluctuations associated with the source mechanism. Finally, it is pointed out that the wave periods are in quasi-resonance with the bounce periods of moderately energetic electrons, and this leads to radial diffusion of such electrons. (Author)

Descriptors :   (*ELECTROMAGNETIC RADIATION, *UPPER ATMOSPHERE), ASTROPHYSICS, PROTON SCATTERING, MATHEMATICAL MODELS, ELECTRONS, ELECTRON DENSITY, DIURNAL VARIATIONS, PLASMAS(PHYSICS), THEORY, EMISSIVITY, RESONANCE SCATTERING, IONOSPHERE, VAN ALLEN RADIATION BELT

Subject Categories : Astrophysics
      Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE