Plasma Injection and Proton Precipitation in the Magnetosphere

S.B. Mende (UC Berkeley, Berkeley, CA 94720), H.U. Frey, P.C. Brandt, 
D. Mitchell

Substorms are an important source for plasma injection into the
magnetosphere. The IMAGE satellite permits the simultaneous observations of
high-energy particles and precipitating particles with the HENA and FUV
instruments respectively. Fluxes from the two instrument sets were compared
by integrating them from different regions of the ENA images and comparing
to the globally integrated precipitating fluxes of protons. This method
permits the relative comparison of the time history of the two data sets
without first performing inversions of the neutral images. From the
examination of several events we show that the trapped particles accumulate
and decay relatively slowly compared to the sudden response observed in the
precipitating flux associated with substorms. Gradual infusion of the
trapped fluxes was also seen in the "growth phase" i.e. during periods prior
to substorm onsets.

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Presentation at the Yosemite Conference of Inner Magnetospheric Interactions,
3 - 6 February 2004, Yosemite, California, USA