On the apparent equatorward propagation of auroral substorm absorption events at low auroral latitudes

Abstract

Auroral substorm absorption events observed at two stations. Val d'Or, P.Q. and Ottawa, Ont., located on the lower latitude side of the auroral zone (around L = 4) show a consistent tendency for an apparent equatorward propagation of the events. The observed velocities of propagation do not show any local time dependence or other trends expected from a pure gradient B drift of substorm electrons from the midnight precipitation region to the day side. Though a limited number of events are analysed the results indicate the possible influence of strong electric fields on the drift velocities of the substorm electrons.