Accession Number:

AD0730826

Title:

Dayside Auroral Oval Plasma Density and Conductivity Enhancements Due to Magnetosheath Electron Precipitation,

Descriptive Note:

Corporate Author:

CALIFORNIA UNIV LOS ANGELES PLASMA PHYSICS GROUP

Personal Author(s):

Report Date:

1971-09-01

Pagination or Media Count:

19.0

Abstract:

Magnetosheath electrons precipitating into the dayside auroral oval are a significant source of ionization and consequently will lead to electrical conductivity enhancements within the oval. By assuming that the electrons are maintained isotropic by strong pitch angle diffusion as they precipitate into the ionosphere, the precipitation heat flux may be simply related to solar wind energy density, and consequently to the level of magnetic activity. For quiet solar wind conditions, the 1 - 10 ergsquare cm-sec heat fluxes expected and observed lead to height-integrated Pederson conductivity enhancements of 4 - 15 mhos. During magnetic storms, the conductivity enhancements could increase by a factor 3 - 5. Since the precipitating electrons are soft, the Hall conductivity enhancements are smaller nevertheless, they lead to field-aligned currents bounding the oval in agreement with observations. The topside ionosphere should also have a density enhancement over the auroral oval on the dayside. Author

Subject Categories:

  • Atmospheric Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE