Interactions between Saturn's neutral gas cloud and >3 keV/Q ions
Abstract
It is well known that energetic protons undergo charge exchange collisions with Saturn's neutral gas cloud and form energetic neutral atoms (ENAs). ENAs are not confined by the planetary magnetic field so they are free to exit the magnetosphere. It has been suggested that this process explains the very low fluxes of energetic protons in Saturn's inner magnetosphere [Paranicas et al., 2008]. Energetic oxygen ions, main components of the so-called water group ions at Saturn, also interact with the same neutrals via charge exchange. However, their distribution in the inner magnetosphere of Saturn seems to be much too high to be consistent with losses via charge exchange alone. In this presentation, we investigate the differences between these two ion populations with observations from Cassini's Charge-Energy-Mass-Spectrometer (CHEMS) and Low Energy Magnetosphere Measurement System (LEMMS). We survey the >3 keV/Q ions in Saturn's magnetosphere on an orbit-by-orbit basis, as long-term averaging of non-uniformly sampled ion distributions may be introducing systematic errors, and compare results to a diffusive transport model with charge exchange losses. We will report our progress in reconciling the differences in the radial intensity gradients inward of ~10 RS between the suprathermal protons and water group ions, which is still an unresolved mystery.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMSM33E3263C
- Keywords:
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- 2756 Planetary magnetospheres;
- MAGNETOSPHERIC PHYSICS;
- 6220 Jupiter;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 6222 Ganymede;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 6275 Saturn;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS