Electron and Proton Auroral Dynamics

S. B. Mende (1), H. U. Frey (1), C. Carlson (1), T. Immel (1), 
J.-C. Gerard (2), B. Hubert (2), S. Fuselier (3), J. Spann (4), 
R. Gladstone (5), J.L. Burch (5)

1 Space Sciences Laboratory, University of California Berkeley,
  Berkeley, CA 94720
2 University of Liege, Liege, Belgium B-4000
3 Lockheed-Martin Palo Alto Research Laboratories, Palo Alto, CA 94304.
4 George C. Marshall Spaceflight Center, Huntsville, AL 35812
5 Southwest Research Institute, San Antonio, Texas

Data from the IMAGE Wide-band Imaging Camera (WIC), sensitive to far 
ultraviolet auroras and from the Spectrographic Imager (SI) channel 
SI12, sensitive to proton precipitation induced Lyman alpha, were 
analyzed during a high altitude orbit segment of the IMAGE spacecraft.   
This segment began during the expansive phase of a substorm.  The 
aurora developed into a double oval configuration, consisting of a set 
of discrete poleward forms and a separate diffuse auroral oval 
equatorwards.  Although IMF Bz was negative, considerable activity 
could be seen poleward of the high latitude arcs in the polar cap 
region.  The optical signature of precipitating protons showed that the 
proton aurora was on the equatorward side of the diffuse aurora and 
there was a lack of intense energetic proton fluxes in the poleward 
arcs.  A simultaneous FAST pass provided a diagnostic of the particle 
types in the various regions.  The data showed that lower intensity 
protons were present throughout the entire double oval configuration but 
with insufficient intensity to be seen by IMAGE.   The FAST data also 
showed that the bright poleward discrete arcs were accelerated by 
electrostatic processes, and the wave accelerated electrons were located 
on the poleward edge of these features.

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Submitted to the Spring 2001 AGU Meeting, Boston, Massachusetts