Space Physics Seminar

Convection in the ionosphere and magnetosphere is driven by solar wind energy, which powers the generation of a large-scale electric field that produces plasma motion. It is generally believed that there are two mechanisms by which solar wind energy generates convection: reconnection and a viscous interaction at the magnetopause. In this talk I propose that a third, fundamentally distinct mode of imposing convection on the magnetosphere and ionosphere exists. Current must flow across the bow shock as determined by the jump conditions, and the bow shock current represents a dynamo. The bow shock current closes in part through the ionosphere, which is a load. Thus it is possible to generate an ionospheric potential that is neither a product of reconnection nor of mechanical transport of energy across the magnetopause. The current-driven potential is imposed directly on the ionosphere by field-aligned currents that connect to the bow shock and which are driven by the mechanical energy extracted from the solar wind as it crosses the bow shock.