A Comparison of the Composition of the Ring Current from IMAGE/HENA with that of
Upflowing Ionospheric Ions from IMAGE/LENA during Magnetic Storms

D.C. Hamilton, K. Retterer, F. Busko, M.R. Collier, T.E. Moore, and S.A. Fuselier, 
D.G. Mitchell, H.D. Voss, K.C. Hsieh

The tendency for the oxygen component of the ring current to increase relative to 
hydrogen in larger geomagnetic storms has been documented.  This trend presumably 
results from enhanced oxygen-rich ionospheric outflow during the more active 
periods associated with large storms with the ionospheric plasma feeding the ring 
current, possibly by way of the plasma sheet.  With the launch of IMAGE we can 
now make simultaneous observations of the ring current and the upflowing ions 
during individual magnetic storms and examine the proposed connection in detail.

In this talk we will present results from four magnetic storms ranging from small 
to large that occurred during the summer of 2000.  We use high energy neutral 
atom data from the HENA instrument on IMAGE as an indicator of the ring current 
composition and low energy neutral atom data from LENA as an indicator of 
upflowing ion composition.  The storm to storm variations will be discussed.

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Submitted to the Spring 2001 AGU Meeting, Boston, Massachusetts