Ionospheric polarization electric field guiding magnetopause reconnection: A conceptual model of throat aurora

Abstract

Frequently observed throat auroras have been suggested to be correspondent to indentations on the subsolar magnetopause, but how these indentations can be generated is unknown yet. Based on analyzing the detailed observational features of throat aurora, a conceptual model for generation of throat aurora is proposed. This model suggests that precipitation of a north-south aligned stripy diffuse aurora can lead to an ionospheric conductivity enhancement and thus produce a polarization electric field in dusk-to-dawn direction in the ionosphere. After mapping to the magnetosphere along closed field lines, this electric field can guide a magnetopause reconnection to develop inward the magnetosphere and result in a throat aurora. Because this model can comprehensively explain all the observational results that have been presented up to now, we argue that the assumption of ionospheric polarization electric field affecting magnetopause reconnection should be true and be worthy of further investigations.