Ion outflow observed by IMAGE: Implications for source regions and heatingmechanisms

Images of the Earth's proton aurora from the IMAGE spacecraft on 8 June 200 0 indicate a temporally and spatially isolated ionospheric response to a sh ock that impinged on the Earth's magnetopause. Sometime after this ionosphe ric response, the Low Energy Neutral Atom imager on IMAGE detected enhanced ionospheric outflow. The time delay between the ionospheric response and t he enhanced outflow is consistent with the travel time of similar to 30 eV neutral Oxygen (created by charge exchange of outflowing O+ with the exosph ere) from the low altitude ionosphere to the spacecraft. The prompt ionosph eric outflow implies that the shock deposited sufficient energy in the tops ide ionosphere near or above the O+ exobase to initiate the outflow.