A mechanism for the production of a disk-shaped neutral source cloud at Io Original Research Article

Io adds of the order of 1000 kg s−1 of ionized material to the jovian magnetosphere. Freshly produced molecular ions, such as SO+ and SO2+, lead to the growth of ion cyclotron waves at frequencies characteristic of their gyro frequencies. These waves are seen over a region about 0.5 RJ radially inward and outward from Io and of similar or greater extent in the down wake direction but not upstream of Io. We examine simplified numerical simulations of the massloading process that preserve the essential physics and demonstrate how this geometry of the massloading region can be created and what we might expect to see on future Galileo Io passes.