A Hybrid Simulation of the Plasma Flow Around Io Coupled to a Multi-species Chemistry Model of Io's Local Interaction.

The Galileo flybys of Io have provided a number of observations that are still not completely understood i.e. the strong asymmetry of the flow and the high plasma density in the center of the wake. Past studies have tackled the problem of the local interaction of Io's corona with the plasma in the torus using different complementary approaches, each of them involving some simplifications: MHD modeling with a parameterization of the sources of ionization and collision (Linker et al., 1998; Combi et al.,1998), 2-fluid approach assuming a constant magnetic field (Saur et al., 1999) and multi-species chemistry assuming a prescribed flow of the plasma around Io (Dols et al.,2008). We couple a hybrid model of the plasma flow around Io (kinetic ions and fluid electrons) and a multi-species chemistry model (chemistry of SO2, S and O) to obtain a fully self-consistent model of the local interaction. We present results of the flow calculation, plasma production and charge exchange rates, pickup current as well as contribution of the electron beams detected close to Io and compare these results with the Galileo flyby observations.