Io's interaction with the jovian magnetosphere causes auroral and radio emissions. This interaction can not be modeled as either an Alfv¿n wave or a steady current loop alone. Given the Galileo measurement of low flow velocities in Io's wake, we argue that the interaction begins as an Alfv¿nic disturbance but as the disturbance is convected downstream it has time to evolve into a steady current loop. We associate high latitude phenomena with different phases of the interaction.¿ 1997 American Geophysical Union