Abstract
While various source and loss processes have been proposed for ions in
Saturn’s magnetosphere, it is not yet well understood what role they
play in different regions. In this study, we use a physical model of
charge exchange to predict how proton and water group ion intensity
profiles evolve over time and compare the results to MIMI/CHEMS
measurements collected during the Cassini mission. First, we divide the
CHEMS data into inbound and outbound half-orbit segments, and create
intensity profiles for 3-220 keV H+ and
W+ ions between 5 and 15 Saturn radii, then using the
inbound half-orbits as initial conditions, we find qualitative
similarities between measured and predicted outbound intensity profiles.
This result is important because it provides strong evidence that charge
exchange is the dominant loss process for these species in this region.
The observed rate of charge exchange also presents information on the
density of Saturn’s neutral torus. We suggest that data-model
discrepancies in the water group ions may be an indication of a
significant presence of ions with the water group mass that are multiply
charged.