Multiple Radially Aligned Plasmaspheric Structures Observed by IMAGE EUV

D.L. Gallagher and M.L. Adrian
National Space Science and Technology Center, NASA/Marshall Space Flight Center, SD50,
Huntsville, AL  35812

R. H. Comfort 
CSPAR, The University of Alabama in Huntsville, Huntsville, AL 35899

J.L. Green
Space Sciences Data Operations Office, Code 630, NASA/Goddard Space Flight Center,
Greenbelt, MD  20771

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


The IMAGE EUV imager has observed several instances where the outer plasmasphere is
populated by multiple, radially aligned structures resembling "plasmaspheric fingers".  On
June 28th these features are found to become bifurcated with increasing distance from the
Earth.  On this day, three enhanced density structures are seen inside about L=2, extended
across about 5 hours MLT.  At larger distances the three structures connect to what appear
to be five distinct, narrow density filaments.  One possible explanation being explored is
the development of a ULF standing wave pattern that causes the observed finger-like plasma
distribution.  An analysis of such line-of-sight observations of He+ ions in the
plasmasphere will be presented.  Possible explanations will be discussed.

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Submitted to the Spring 2001 AGU Meeting, Boston, Massachusetts