Oxygen in the ring current during major storms, IMAGE/HENA results

D. G. Mitchell, P. C. Brandt
The Johns Hopkins University Applied Physics Laboratory (don.mitchell@jhuapl.edu)

Since August 2001, IMAGE/HENA has had the capability to image energetic neutral
atom (ENA) emissions from the ring current in both hydrogen and oxygen, separately.
We have found that the 100 to 250 keV oxygen emission is generally well correlated
with substorm activity during major storms, while the 16 to 60 keV hydrogen 
emission is poorly correlated with substorm activity (although well correlated with 
Dst index). The 60 to 120 keV hydrogen exhibits some characteristics of both the 
lower energy hydrogen, and the higher energy oxygen. In this paper, we explore the 
spatial development of the emission for hydrogen at both energies, as well as for 
energetic oxygen. While we are hampered by relatively poor angular resolution in 
the oxygen images, we will try to separate the effects of pitch angle scattering 
and precipitation from the effects of injection into the high altitude ring 
current, as the source of the oxygen enhancements that are observed.

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Presented at the 34th COSPAR Scientific Assembly, Houston, Texas, U.S.A.  
10-19 October 2002