Characteristics of auroral electron precipitation on the morningside

Quantitative information on auroral electron precipitation is needed to evaluate the effects of the precipitation on the ionosphere and upper atmosphere. In this paper we present such information for the mormingside aurora. We use simultaneous observations of precipitating electrons and auroral images from the low-altitude, polar-orbiting DMSP-F6 satellite, and we relate specific precipitation features to specific types of auroras. We find the equatorward region of diffuse aurora to have precipitating electron energy fluxes, epsilon-c/sub p/, which typically reach 10 ergs/cm2 s, and such fluxes can extend over several degrees in latitude. Energy spectra over the diffuse aurora are quite hard and show no evidence of acceleration by a field-aligned potential drop, V/sub parallel/. The poleward region of structured aurora includes a soft background of relatively weak, uniform precipitation. Arclike structured precipitation results from variable V/sub parallel/ acceleration of this background. Over the arcs, epsilon-c/sub p/ can exceed 1 erg/cm2 s