FUV Global View of the Evolution of Electrons and Protons Substorms

M. Meurant (1), B. Hubert (1), J.C. Gerard (1), S.B. Mende (2)

(1) Laboratoire de Physique Athmospherique et Planetaire, Universite de
    Liege, Belgium (mmeurant@ulg.ac.be / Fax: 04/366.97.11)
(2) Space Science Laboratory, University of California, Berkeley


The FUV instruments on board the IMAGE satellite provide global images
of the N2-LBH (WIC), OI-1356 \AA (SI13) and Doppler shifted Lyman-alpha
(SI12) emissions of the north polar aurora. The 7 Re apogee of the IMAGE
orbit allows FUV to simultaneously image the entire auroral zone during a
large fraction of the orbit.  We present a result of a study of the global 
morphology evolution during substorm development and recovery. In order to 
avoid any dayglow contamination, this study is restricted to winter 
observation. In active regions, electron fluxes and electrons mean 
energies are deduced assuming a Maxwellian distribution assumption. The 
mean energy is derived from the WIC/SI13 ratio. Proton fluxes are also 
determined assuming  a 8 keV proton mean energy with a Kappa distribution. 
The temporal dependence of the electron and proton injections is studied 
along with their magnetic local time and magnetic latitude variations 
during several substorms. In particular, the temporal evolution of the 
magnetic latitude of the bulk proton and electron injections is presented. 
Our results are found to be consistent with previous studies resting on 
ground based observations.

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To be presented at the 2002 Spring A.G.U. Meeting, 
Washington, D.C., U.S.A., 28-31 May 2002