Plasmaspheric Electron Density Distributions Sampled by Radio Plasma
Imager on the IMAGE Satellite

Shing F. Fung(1), Leonard N. Garcia(2), James L. Green(1),
Dennis L. Gallagher(3), Donald L. Carpenter(4), Bodo W. Reinisch(5),
Ivan A. Galkin(5), Grigori Khmyrov(5), and Bill R. Sandel(6)

1 NASA GSFC, Greenbelt, MD
2 Raytheon ITSS / NASA GSFC, Greenbelt, MD
3 NASA MSFC, Huntsville, AL
4 STAR Lab, Stanford University, Stanford, CA
5 Center for Atmospheric Research, University of Massachusetts, Lowell, MA
6 Lunar & Planetary Laboratory, University of Arizona, Tucson, AZ


Distribution of plasmaspheric density changes in response to plasma
electrodynamical processes in both the ionosphere and magnetosphere.
During a geomagnetic storm, for example, the plasmasphere can
significantly diminish in size during the main phase of the storm and
relax to regain its more normal size during recovery phase. During
unusually quiet times, the plasmasphere can become quite large. The
processes by which the plasmasphere is eroded and refilled are still
areas of active research. Previous in situ observations (e.g., CRRES)
have shown that the plasmasphere has a lot of structures, quite possibly
results of plasma dynamical processes. Recent global EUV images obtained
by IMAGE also reveal large-scale plasma structures as well as
large-scale variations of the plasmasphere resulting from magnetospheric
activities. In this paper, we investigate the large-scale plasmaspheric
density variations as a function of solar wind and geomagnetic
activities by analyzing a large collection of passive RPI observations
of quasi-thermal noise through the plasmasphere obtained over the first
year of the IMAGE mission. We will compare our results with existing
models of plasmaspheric density distributions.


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