Plasma Regions Around Enceladus
Abstract
Enceladus, and ionised material in the south polar plume strongly influences the magnetospheric environment around the moon. In this study the focus is set to the downstream region and the edge of the plume. This is an overview of the electron density measurements by the Langmuir probe of the Radio and Plasma Wave Science (RPWS) instrument on Cassini of all flybys performed. We present measurements of the electron and ion density, and magnetic field, which clearly show the different plasma regions of the Enceladus interactions. There have been four high inclination flybys passing directly though the downstream region of Enceladus where a wake could be expected (E3-E6). In these, an electron density decrease is observed where on the other hand the ion density stays constant. See figure 1 (top) as an example. A likely explanation for this mismatch between densities is electron absorbtion by micrometer size dust particles, which suggests that the dust is not only contained in the plume but spreads into a larger volume. At the edge of the plume a decrease in electron density has been consistently observed in flybys parallel to the equatorial plane, see figure 1 (bottom). This may also be a consequence of electron absorbtion by dust, counteracted in the center of the plume by an increased gas density acting as a plasma source.
- Publication:
-
European Planetary Science Congress
- Pub Date:
- April 2014
- Bibcode:
- 2014EPSC....9..735E