Accession Number : AD0282743

Title :   WHISTLER ATTENUATION BY ELECTRONS WITH AN E-2.5 DISTRIBUTION

Corporate Author : BOEING SCIENTIFIC RESEARCH LABS SEATTLE WASH

Personal Author(s) : LIEMOHN,H.B. ; SCARF,F.L.

Report Date : JUN 1962

Pagination or Media Count : 1

Abstract : The thermal (Landau) attenuation of natural whistler radiation is examined assuming that the electron component has a velocity distribution of the (Cauchy) form (v2 + a2)-3 which corresponds to an energy dependence of E-2.5 when v >> a. A temperature of 105 K at R 4Re geocentric is required in order to explain the observed cutoff at 0.6 c(0 ) where c(0 ) is the minimum cyclotron frequency along the path. A simple algebraic expression is obtained for the electron temperature which makes the analysis of a large number of whistler traces feasible. The exact shape of the distribution and the concept of temperature are only relevant in the sense that they give the fraction of electrons which participate in the damping interaction at the Doppler shifted phase velocity vo( ) = ( - c) /Re k( ). For a total density of 200 electrons/cm3 at R 4Re, the thermal attenuation mechanism predicts and electron flux of 4 x 105 electrons/cm2 sec eV for energies near 250 eV. (Author)

Descriptors :   *ATTENUATION, *DAMPING, *DISTRIBUTION, *ELECTROMAGNETIC RADIATION, *ELECTRONS, *EXTREMELY LOW FREQUENCY, *TEMPERATURE, EXOSPHERE

Distribution Statement : APPROVED FOR PUBLIC RELEASE