Accession Number : ADP005695

Title :   Hostile Energetic Particle Radiation Environments in Earth's Outer Magnetosphere,

Corporate Author : LOS ALAMOS NATIONAL LAB NM

Personal Author(s) : Baker, D. N. ; Belian, R. D. ; Higbie, P. R. ; Klebesadel, R. W. ; Blake, J. B.

Report Date : MAY 1987

Pagination or Media Count : 16

Abstract : Three types of naturally-occurring, and highly variable, hostile transient particle radiation environments are encountered at, or near, spacecraft geostationary orbits: (1) High-energy protons due to solar flares; (2) Energetic ions and electrons produced by magnetospheric substorms; and (3) Very high energy electrons of uncertain origin. In this paper, emphasis is given to highly relativistic electrons (3 to approx. 10 MeV). Electron fluxes and energy spectra are shown which were measured by two high-energy electron sensor systems at 6.6 earth radii frm 1979 - 1984. Large, persistent increases in this population were found to be relatively infrequent and sporadic in 1979-81 around solar maximum. During the approach to solar minimum (1981-present) it is observed that the highly relativistic electrons occur with a regular 27-day periodicity, and are well associated with the re-established solar wind stream structures. A superposed epoch analysis technique shows that an energetic electron enhancement typically rises on a 2- to 3-day time scale and decays on 3- to 4-day time scale at essentially all energies above approx. MeV.

Descriptors :   *MAGNETOSPHERE, *ELECTRONS, ENERGETIC PROPERTIES, CHARGED PARTICLES, HIGH ENERGY, SOLAR FLARES, MAGNETIC STORMS, ELECTRON ENERGY, ELECTRON FLUX, PERIODIC VARIATIONS, SOLAR CYCLE, SOLAR WIND, ADVERSE CONDITIONS, TRANSIENT RADIATION EFFECTS, SYNCHRONOUS SATELLITES, EARTH(PLANET), JUPITER(PLANET), SPACECRAFT, ELECTRIC CHARGE.

Subject Categories : Atmospheric Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE