Accession Number : ADA131263

Title :   Evidence of East-West Structure in Large-Scale F-Region Plasma Enhancements in the Auroral Zone.

Descriptive Note : Technical rept.,

Corporate Author : SRI INTERNATIONAL MENLO PARK CA

Personal Author(s) : Tsunoda,Roland T ; Vickrey,James F

PDF Url : ADA131263

Report Date : 01 May 1982

Pagination or Media Count : 43

Abstract : Large-scale (10- to 100-km) plasma-density enhancements appear to be an integral feature of the auroral F-layer ionosphere. These enhancements, called F-region blobs, have been detected with the Chatanika incoherent-scatter radar, and are particularly noticeable during recent years of high solar activity. Blobs have attracted considerable interest because of their propensity for structuring, apparently via the gradient-drift and current-convective instabilities. Although both mechanisms predict the generation of longitudinal structure, no measurements have been made to verify this hypothesis. In this report, we present the first direct evidence that blobs have east-west structure. The observed longitudinal structure is shown to be consistent with the production of a blob by locally intense particle precipitation at the largest scales (approx. 500 km) and the structuring of the blob by the gradient-drift instability at intermediate scales (similar to 150 km). (Author)

Descriptors :   *Plasmas(Physics), *Density, *F region, Aurorae, Ionosphere, Gradients, Drift, Experimental data, Electric fields, Polar cap

Subject Categories : Atmospheric Physics
      Plasma Physics and Magnetohydrodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE