Survey of the Plasma Composition in Saturn's Magnetotail

Friday, 19 December 2014
Marianna Felici1, Christopher Stephen Arridge1,2, Daniel Brett Reisenfeld3, Michelle F Thomsen4 and Andrew J Coates1, (1)University College London, Mullard Space Science Laboratory, London, United Kingdom, (2)University of Lancaster, Department of Physics, Lancaster, United Kingdom, (3)University of Montana, Department of Physics & Astronomy, Missoula, MT, United States, (4)Planetary Science Institute, Los Alamos, NM, United States
The Cassini mission has orbited Saturn since 2004, but in 2006 it explored the deep magnetotail, reaching distances of about 68 Rs (where Rs is the equatorial radius of Saturn). In one event from 30 Rs in the tail we have identified cold plasma which we interpret as polar wind outflow from Saturn and where the surrounding plasma sheet has an unusual composition (Felici et al., in preparation). This raises the question of what is the typical and atypical composition in different regions of the magnetotail. Previous compositional studies have mostly focused on regions of the magnetosphere inside of 17 Rs (Young et al., 2005; Thomsen et al., 2010) and in this paper we present a survey of the bulk plasma composition using time-of-flight data from the CAPS/IMS instrument on Cassini. The results are organised by radial distance and local time in order to examine sources and sinks of plasma in the magnetotail and their time dependence.