Relations Among Complex Spatial Structures in the Plasmasphere

Bill R. Sandel, Robert A. King, and W. T. Forrester

We investigate complex spatial structures within the plasmasphere, with 
the goal of improving our understanding of the relationships among them. 
With our new ability to determine the distribution of cold plasma near 
Earth, it is not surprising that many structures have appeared that had 
not previously been specifically addressed by theory and modeling efforts. 
Now modeling of some of these structures is underway, so a better 
understanding of them is needed. We focus on the possible relationships 
among time-variable structures such as convection tails, large-scale 
scallops in the shape of the plasmapause, azimuthal channels of low density 
in the pre-midnight sector, and possible departures from corotation in the 
same region. The observations that we use here come from the Extreme 
Ultraviolet Imager (EUV) of the IMAGE Mission. Encompassing the entire 
plasmasphere in a single frame, EUV records the spatial distribution of He+ 
with a time resolution of 10 minutes and a spatial resolution of 0.1 Re or 
better. EUV measures the brightness of 30.4-nm sunlight resonantly 
scattered by He+ surrounding Earth.

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Submitted to the Spring AGU Meeting, Boston, Massachusetts, 29 May - 2 June 2001