Evidence for Subauroral Electric Fields from IMAGE EUV

D. Gallagher, M. Adrian, J. Goldstein, B. Sandel


The IMAGE Mission Extreme Ultraviolet Imager routinely provides global
snapshots of the plasmasphere from high latitude.  In these 10-minute
images, intensity edges have been identified with the plasmapause and other
strong gradients in plasmaspheric density.  In addition to the classic
sunward directed convection tail and its entrainment in corotation during
storm-time recovery, the plasmapause boundary reveals a wide variety of
structures thought to result from penetration of the solar wind induced
convection electric field to subauroral latitudes.  The so-called shoulder
feature has most prominently been discussed in the context of under
shielding in response to changes in the convection electric field strength.
It is not yet clear whether all of the observed surface structures on the
plasmasphere can be explained in this manner.  The types of structures
observed and their frequency of occurrence will be presented.  A statistical
view of these structures and associated solar wind conditions will also be
presented.

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Fall 2002 Meeting of the American Geophysical Union
San Francisco, CA, USA, 6-10 December 2002