Plasmaspheric erosion via plasmasphere coupling to ring current plasmas: 
EUV observations and modeling

M.L. Adrian, D.L. Gallagher, G.V. Khazanov, and S.-W. Chang
Science Directorate, SD50, NASA/Marshall Space Flight Center, 
Huntsville, AL  35812

M.W. Liemohn,
Space Physics Research Laboratory, University of Michigan, Ann Arbor, MI 48109

J.D. Perez
Department of Physics, Auburn University, Auburn, AL 36849

J.L. Green
National Space Science Data Center, Code 630, NASA/Goddard Space Flight Center, 
Greenbelt, MD  20771

B.R. Sandel
Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ  85721

D.G. Mitchell
Applied Physics Laboratory, John Hopkins University, Laurel, MD 20810

S.B. Mende
Space Sciences Laboratory, UC Berkeley, Berkeley, CA 94720


During a geomagnetic storm on 24 May 2000, the IMAGE Extreme Ultraviolet (EUV) 
camera observed a plasmaspheric density trough in the evening sector at L-values 
inside the plasmapause.  Forward modeling of this feature has indicated that 
plasmaspheric densities beyond the outer wall of the trough are well below model 
expectations.  This diminished plasma condition suggests the presence of an 
erosion process due to the interaction of the plasmasphere with ring current 
plasmas.  We present an overview of EUV, energetic neutral atom (ENA), and Far 
Ultraviolet (FUV) camera observations associated with the plasmaspheric density 
trough of 24 May 2000, as well as forward modeling evidence of the existence of 
a plasmaspheric erosion process during this period.  FUV proton aurora image 
analysis, deconvolution of ENA observations, and ring current modeling are then 
presented in an effort to associate the observed erosion with coupling between 
the plasmasphere and ring-current plasmas.

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To be presented at the 2002 Spring A.G.U. Meeting, 
Washington, D.C., U.S.A., 28-31 May 2002