At very high latitudes, existing data and theoretical models suggest there may be isolated patches of energetic electron precipitation into the atmosphere. Islands of energetic electrons have frequently been observed in the geomagnetic tail /1,2,3/. Also, theoretical studies have advanced the idea of localized plasma entry through the magnetopause involving clouds or plasmoids /4/. With direct particle measurements, Hoffman and Evans /5/ observed a “burst region” poleward of the auroral oval that was characterized by a very soft spectrum and large structures in the precipitation patterns. The sporadic and structured precipitation of soft electrons over the polar caps has been observed by Winningham and Heikkla, /6/. Higher energy spikes have been observed at high latitudes by McDiarmid and Burrows /7/ for > 40 keV electrons and by Brown and Stone /8/ for > 425 key electrons. However, the structured precipitation of electrons at high latitudes is not well understood due to the two— dimensional character, the confined extent and the temporal variations. For energetic electrons even less is known due to limitations in the available data.
