The interaction of the solar wind with ionized gas confined by the earth's magnetic field results in a long extension downwind to many earth radii of the magnetic field and gas (the magnetosphere) and the generation of currents of millions of amperes which flow through the high latitude ionosphere, and create the striking displays of light emission known as the aurora. This award is for the continuation of a cooperative observation and analysis program called GISMOS, of which several successful campaigns have taken place, using radar and optical and magnetic field measuring equipment to determine the pattern of electric field associated with the currents and auroral emissions. The objective is to advance our understanding of the physical processes involved in the sudden release of energy previously accumulated in the magnetosphere by the solar wind- magnetosphere interaction, part of which is deposited in the ionosphere and is known as a magnetic substorm.