Global comparison of proton aurora and trapped particle dynamics

J.-M. Jahn (1), H. U. Frey (2), M. G. Henderson (3), T. J. Immel (2), S. B. Mende (2), 
C. J. Pollock (1), G. D. Reeves (3), R. Skoug (3), and M. F. Thomsen (3)

(1) Southwest Research Institute, Space Science Department, San Antonio, TX 78238, USA
    (jjahn@swri.edu/Fax:+1-210-520-9935)
(2) University of California, Space Science Lab, Berkeley, CA 94720, USA
(3) Los Alamos National Laboratory, NIS-1, Los Alamos, NM 87454, USA

With recent IMAGE energetic neutral atom (ENA) observations we can globally correlate
the dynamics of precipitating proton auroral phenomena with the dynamics of
non-precipitating plasma, tying processes at different portions along magnetic field
lines together. We present comparisons for IMAGE FUV proton aurora and IMAGE MENA 
medium energy neutral atom (ENA) observations of isolated and storm-time substorm 
events during the time period 2000 to 2002, supplemented by Los Alamos geosynchronous 
in situ plasma measurements. We compare remotely sensed particle fluxes during the 
growth, expansion and recovery phase of isolated substorms. The proton auroral 
response is typically both quicker and stronger, with significant flux increases over 
short periods of time. The ENA response is typically slower and more gradual. In 
addition, enhanced flux levels will persist up to several hours, much longer than the, 
by comparison, short-lived auroral displays. While this represents a considerable
difference in the time evolution of an event, the magnetic local time extent of
precipitating and trapped particles tracks much more closely. We will compare this
behavior to in situ plasma measurements at geosynchronous altitudes. We will also
discuss how ENA signatures of isolated substorms compare to storm-time events.

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