Accession Number : AD0468149

Title :   A LIMIT ON STABLY TRAPPED PARTICLE FLUXES.

Descriptive Note : Research rept.,

Corporate Author : AVCO EVERETT RESEARCH LAB EVERETT MASS

Personal Author(s) : Kennel,C. F. ; Petschek,H. E.

Report Date : JUL 1965

Pagination or Media Count : 61

Abstract : Whistler mode noise leads to electron pitch angle diffusion. Similarly, ion cyclotron noise couples to ions. This diffusion results in particle precipitation into the ionosphere and creates a pitch angle distribution of trapped particles which is unstable to further wave growth. Since excessive wave growth leads to rapid diffusion and particle loss, the requirement that the growth rate be limited to the rate at which wave energy is depleted by wave propagation allows a estimate of an upper limit to the trapped equatorial particle flux. Electron fluxes greater than 40 keV and proton fluxes greater than 120 keV observed on Explorers XIV and XII respectively obey this limit with occasional exceptions. Beyond L = 4, the fluxes are just below their limit, indicating that an unspecified acceleration source sufficient to keep the trapped particles near their precipitation limit exists. Limiting proton and electron fluxes are roughly equal, suggesting a partial explanation for the existence of larger densities of high energy protons than electrons. Observed electron pitch angle profiles correspond to a diffusion coefficient in agreement with observed lifetimes. The required equatorial whistler mode wide band noise intensity, 0.001 gamma is not obviously inconsistent with observations, and is consistent with the lifetime and limiting trapped particle intensity. (Author)

Descriptors :   (*WHISTLERS, ELECTRONS), (*IONOSPHERIC DISTURBANCES, WHISTLERS), UPPER ATMOSPHERE, IONS, ELECTRON DENSITY, PROTONS, VERY LOW FREQUENCY, MAGNETIC FIELDS, ELECTRIC FIELDS, REFRACTIVE INDEX, TURBULENCE, DIFFUSION

Distribution Statement : APPROVED FOR PUBLIC RELEASE