Kinetic simulations of the Jovian ion circulation around Ganymede and space weather implications

The exosphere of Jupiter’s moon Ganymede is the interface region linking the moon’s icy surface to Jupiter’s magnetospheric environment. Space weather phenomena driven by the variability of the radiation environment within the Jupiter system can have a direct impact on the sputtering-induced exosphere of Ganymede.

In this work we simulate the Jovian ion precipitation to Ganymede’s surface for different moon orbital phases around Jupiter. In particular, we consider three different configurations between Ganymede’s magnetic field and Jupiter plasma sheet, similar to those encountered during the Galileo G2, G8, and G28 flyby (i.e., the moon above, inside, below the Jupiter plasma sheet). We discuss the differences between the various ion precipitation patterns and the implications in the density distribution of the sputtered-water exosphere of this moon. We also comment the possible relation of these ion precipitation patterns with the surface brightness asymmetries both between Ganymede’s polar cap and equatorial regions and between the leading and trailing hemispheres. The results of this preliminary analysis are relevant to the JUICE mission and in particular to the preparation of the future observation strategies for the environment of Ganymede.