Electrons at Enceladus: recent encounters

During two North-South directed encounters of Enceladus in 2008, negative ions and charged nanograins were discovered in the Enceladus plume by the CAPS instrument. The low energy negative ions are principally water clusters (Coates et al., Icarus in press 2009), the high energy signatures were identified as negatively and positively charged nanograins and were associated with surface features (Jones et al., GRL 2009); also, stagnation of the magnetospheric flow around a cold water-dominated plume ionosphere was observed (Tokar et al, GRL 2009). In late 2009, the Cassini spacecraft will make two lateral traverses through the plume at different distances from Enceladus. Here we summarise the observations and present a first look at the electron data from CAPS from the 2009 encounters, which are expected to provide fresh perspectives on negative ions and charged nanograins.