Observations of the Geopause at the Equatorial Magnetopause

M. O. Chandler and T. E. Moore


Magnetic flux tubes containing plasmaspheric ion density and composition have
been observed in the region between the classical plasmapause and the
magnetopause. New observations show that these ion distributions exist at the
equatorial, post-noon magnetopause. Comparison to observations of similar
distribution at geosynchronous orbit and to simulations leads to the
conclusion that these ions are convected from these regions to the
magnetopause. This represents an extension of the geopause to the outer edge
of the magnetosphere on the dayside. The presence of ion densities 10cm-3 in
this region must have profound impact on the nature of plasma processes that
occur there.

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Presented at the Magnetospheric Imaging Workshop, 
Yosemite National Park, California, U.S.A., Feb. 9 - 13, 2003.