Alfven Wave Propagation in the Io Plasma Torus

Io, the most volcanically active body in the solar system, fuels a plasma torus around Jupiter with dissociation products of SO2 at a rate of similar to 1,000 kg/s. We use a combination of in situ Voyager 1 data and Cassini Ultraviolet Imaging Spectrograph observations to constrain a diffusive equilibrium model of the Io plasma torus. The interaction of the Io plasma torus with Io launches Alfven waves in both directions along magnetic field lines. We use the recent Juno-based JRM09 magnetic field model combined with our 3-D model of the Io plasma torus to simulate the propagation of Alfven waves from the moon to the ionosphere of Jupiter. We map the location of multiple reflections of iogenic Alfven waves between the northern and southern hemispheres. The location of the first few bounces of the Alfven wave pattern match the Io auroral footprints observed by the Hubble Space Telescope.