The effects of time-variation of electron fluxes from the auroral ionosphere on M-I coupling

Abstract

Electric potential-differences between the magnetospheric and the ionospheric end of a magnetic flux tube lead to the downward acceleration of electrons in the ionosphere, producing visible auroral arcs. Most of the potential-drop is situated in a narrow altitude-region known as double layer. In the ionosphere, the precipitation of high-energy electrons will produce secondary electrons. Some of the primary and secondary electrons will escape out of the ionosphere back up along the magnetic flux tube. In this work, we study the dynamic effects from the onset of upward-streaming electrons from the ionosphere on a double layer potential structure situated in the acceleration region. We find that the onset of the upward-streaming electrons is the source of perturbations in the electric field between the double layer and the ionosphere. The perturbations do not seem to affect the structure of the double layer, but have an effect on the precipitation of electrons.