Electron microsignatures from the Saturnian satellites: Cassini MIMI/LEMMS observations
Abstract
Since the Saturn Orbit Insertion in July 2004, Cassini has performed numerous crossings of Saturn's inner moons L-shells at various longitudinal distances from the moons. The Low Energy Magnetospheric Measurement System (LEMMS) has detected a significant number of absorption features, referred to as microsignatures, in the the lowest energy electron channels (20-200 keV). The detections occur mainly in the vicinity of Tethys and Dione L-shells, while microsignatures from Enceladus, Rhea and Mimas are less frequent. From the analysis of these features we present: (i) estimates of the radial diffusion coefficient in Saturn's radiation belts as a function of L and energy, including for the first time their dependence on local time, (ii) the region of influence that the electric fields and energetic events (e.g. injections) have on the electron drift shells and (iii) the implications for the unique interaction characteristics of each moon with Saturn's magnetospheric plasma. Data from the recent close flybys of Tethys, Dione and Rhea are also briefly discussed.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2005
- Bibcode:
- 2005AGUFM.P43A0955R
- Keywords:
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- 2730 Magnetosphere: inner;
- 2732 Magnetosphere interactions with satellites and rings;
- 2740 Magnetospheric configuration and dynamics;
- 2774 Radiation belts;
- 2778 Ring current