Accession Number:

ADP005695

Title:

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

Descriptive Note:

Corporate Author:

LOS ALAMOS NATIONAL LAB NM

Report Date:

1987-05-01

Pagination or Media Count:

16.0

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.

Subject Categories:

  • Atmospheric Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE