Satellite sputtering in Saturnʹs magnetosphere

The heavy ion plasma and energetic particles continuously sputter the surfaces of the icy satellites embedded in the inner Saturnian magnetosphere. We evaluate satellite sputtering and compare the resulting H2O source distribution with the source distribution expected for the OH cloud recently observed by Hubble Space Telescope. At each satellite we combine, for the first time, the data from the Plasma Science (PLS) and Low Energy Charged-Particle (LECP) instruments from Voyager 1 and 2, unifying them into a single plasma distribution function. Based on the calculated satellite sources, we conclude that sputtering of the satellite surfaces cannot produce the observed OH cloud and that a large additional source in the inner magnetosphere is needed to fully explain the HST observations.