Tomographic reconstruction of plasma density via latitude variation model 
parameter recovery, 

Cuilan Wang, Timothy S. Newman, Dennis L. Gallagher


A new method for reconstructing the density of plasma throughout the terrestrial
plasmasphere is introduced. The method is a tomographic approach that utilizes a
series of NASA IMAGE Extreme Ultra Violet (EUV) images collected over a short
time span. The reconstruction recovers positional densities through a robust
fitting process that determines parameters of a latitudinally varying model of
the plasma density distribution.  This non-linear model, proposed by Huang et
al. (2004) is based on observation in IMAGE RPI data and requires determination
of 5 parameters for each magnetic meridian plane. The fitting processes uses
Levenberg-Marquardt based nonlinear least squares to determine the set of
parameters based on the series of image views, and from these parameters, the
plasmaspheric plasma distribution is then estimated. Results on clean synthetic
data suggest a recovery error of less than 1%.  Test on real EUV data suggest
about a 5% error in recovery. The appearance characteristics of recovered plasma
distributions also appear to visually well-match real EUV data.

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Fall Meeting, American Geophysical Union, San Francisco, U.S.A., 2005