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 use of radar and optical and magnetic field measuring equipment to determine the pattern of electric fields associated with the currents and auroral emissions, to help in understanding the physical processes that take place at the boundary between the solar wind and the magnetosphere.