Space Borne Optical Remote Sensing of Midday Auroral Oval and Different Participation Regions

Abstract

This paper very briefly summarizes an invited talk given at the Polar Cusp Conference in Norway, 1993. A more complete version could not be presented here due to a limitation of the length of the paper and a need for a large amount of color diagrams. Three topics were discussed. By using the simultaneous DMSP observations of midday auroral imagery and soft particle precipitations, we examined the location of the polar cusp proper (defined from electron and ion characteristics) with respect to the broad band visible midday auroral displays. The second topic was the midday auroral observations made by the Far Ultra Violet (FUV) monochromatic imager onboard the Polar Bear satellite. The FUV monochromatic imaging technique opened a new era in magnetospheric and atmospheric research, since it enabled us to “see” from space the global auroral displays under “all-weather” condition, independent of season and daynight conditions. The third topic covered whether optical remote sensing from a space platform could be used to project different magnetospheric source regions onto the ionosphere. Based on an atmospheric emission model with inputs using various particle (both electrons and ions) precipitation features of magnetospheric plasma source regions (namely, the polar cusp, polar rain, mantle, low latitude boundary layer, boundary plasma sheet, central plasma sheet etc.), we determined that remote sensing of the instantaneous distribution of plasma regions (i.e., a projection of magnetospheric configuration) is feasible when several simultaneous optical emission lines are used to image the dayside part of auroral oval and adjacent regions.