An update on the ring exosphere and plasma disc of Saturn

Abstract

A re-examination of the mass budget of the ring exosphere of Saturn - as prompted by the most recent Cassini measurements in the vicinity of the ring system - indicates that the corresponding number density could reach the level of 2-3 × 10⁵ cm^-3 at maximum. Such extended exospheric structure in equilibrium with a thin ring plasma disc could be an important supplier of suprathermal oxygen ions of a few tens of keV in the Saturnian magnetosphere.