All Physics Faculty Publications

Penetration of high latitude electric fields effects tolow latitude during Sundial 1984

Document Type

Article

Journal/Book Title/Conference

Annales Geophysicae

Volume

6

Issue

39

Publisher

European Geosciences Union

Publication Date

1988

Abstract

Using F-region vertical-drift measurements made at selected times in the interval October 6-13, 1984, by the Jicamarca incoherent-backscatter radar and corresponding h'F measurements from ionosondes at Fortaleza, Cachoeira Paulista and Dakar, several instances of electric-field-penetration events are identified and compared with previously established low-latitude signatures. These events are interpreted in terms of a set of computer runs made with the Rice Convection Model through an idealized substorm, which included a sharp increase and subsequent decrease in the strength of magnetospheric convection. Several computer experiments were performed to determine the sensitivity of electric-field penetration to several input parameters of the magnetospheric model. The magnetic-field model was held constant in these runs. It was determined that, for constant plasma pressure p, a hot plasma sheet allows significantly greater overall electric-field penetration than a cold plasma sheet; poor shielding results for even relatively long time periods, if the plasma sheet remains hot. Comparison of model results with the observations leads to the following conclusions: 1. With regard to the low-latitude electric field that occurs promptly in response to an increase in high-latitude convection, the model-calculated pattern, strength, and duration are satisfactorily consistent with observations; 2. For the case of low-latitude electric fields resulting from a decrease in magnetospheric convection, model calculations performed under the assumption of zero neutral wind are consistent with the observations with regard to pattern and maximum strength, but not with regard to duration; 3. The most promising theoretical explanation for the observed 1-2 h duration of the low-latitude response to decreased convection seems to be the ''fossil-wind'' idea suggested by A.D. Richmond

This document is currently not available here.

Share

COinS