COUPLING THE PLASMA INTERACTION AT IO TO JUPITER

Io's interaction with the jovian magnetosphere causes auroral and radi o emissions. This interaction can not be modeled as either an Alfven w ave or a steady current loop alone. Given the Galileo measurement of l ow flow velocities in Io's wake, we argue that the interaction begins as an Alfvenic disturbance but as the disturbance is convected downstr eam it has time to evolve into a steady current loop. We associate hig h latitude phenomena with different phases of the interaction.