Three-dimensional extension of the Io UV footprint emissions

The Io UV footprint is an auroral feature observed close to the feet of the field lines passing through Io on both Jovian hemispheres. These light emissions are caused by the electromagnetic interaction between the satellite Io and the Jovian magnetosphere. For both the north and south poles, the Io footprint appears as a bright spot followed by a faint trailing tail and occasionally followed or preceded by secondary spots. The footprint morphology and the spots multiplicity have been found to vary with the location of Io in the plasma torus.