Survey of the Plasma Composition in Saturn's Magnetotail
Open Session on Magnetospheric, Ionospheric and Solar-Terrestrial physics
Marianna Felici
C.S. Arridge (Lancaster University, UK.), D.B. Reisenfeld (University of Montana, USA. ), M.F. Thomsen (Planetary Science Institute, Tucson, Arizona, USA), A.J. Coates (Mullard Space Science Laboratory, UCL, UK)
) Mullard Space Science Laboratory, UCL, UK
In a case study of Cassini data from Saturn’s magnetotail we have found evidence for cold plasma flowing away from Saturn in the magnetotail lobes which we interpret as polar wind outflow from Saturn (Felici et al., in preparation). The surrounding plasma sheet during this event has an unusual composition showing very low fluxes of water group ions – essentially the plasma sheet is entirely composed of H+ at a distance of 36 RS in the pre-midnight sector. 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; Wilson et al., submitted) 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. We show the average plasma composition organised by radial distance and local time and also study the variability in the composition. Our overall aim is to understand the sources and sinks of plasma in the magnetosphere, leading to the observed variability, and how this might vary with time and upstream conditions.


09:00 - 10:30