Accession Number : AD0775168

Title :   Geomagnetically Trapped Alpha Particles. Low-Altitude Outer-Zone Alpha-Proton Comparisons.

Descriptive Note : Rept. for Nov 72-Apr 73,


Personal Author(s) : Fennell,Joseph F. ; Blake,J. Bernard ; Paulikas,George A.

Report Date : 15 JAN 1974

Pagination or Media Count : 40

Abstract : The outer-zone population of trapped alpha particles and protons was measured off the equator (B/Bo = 1.3-2.3) in the L interval 2 = or < L = or < 4 during 1969. The alpha-particle spectra are best represented by a power law with spectral indices between 2.4 and 4.0 over the energy range 0.85 = or < (E sub alpha) = or < 9.0 MeV. The alpha-particle and proton spectra have the same slope at the same total energy. The distribution functions for alpha particles and protons have similar shapes and they suggest that the location of the source of these particles is at L > 4. The proton pitch-angle distribution at small pitch angles is flatter than near the equator. It is suggested that pitch-angle scattering may be the primary source of the low-altitude ions. The measurements are compared with recent theoretical predictions. (Modified author abstract)

Descriptors :   *Van Allen radiation belt, *Alpha particles, *Protons, Distribution, Energy, Spectra

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE