FUV Global View of the Evolution of Electrons and Protons Substorms

The FUV instruments on board the IMAGE satellite provide global images of the N2-LBH (WIC), OI-1356 Ì· (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.