HR: 1330h
AN: SM22B-0247    [PDF]
TI: The Ionosphere and Plumes of Europa
AU: * Eviatar, A
EM: arkee@daphne.tau.ac.il
AF: Tel Aviv University, Ramat Aviv, Tel Aviv, 69978 Israel
AU: Paranicas, C
EM: Chris.Paranicas@jhuapl.edu
AF: Applied Physics Laboratory Johns Hopkins University, Johns Hopkins Road, Laurel, MD 20723 United States
AB: We investigate the proposition that Europa emits a plasma plume, {\em i.e} a contiguous body of ionospheric plasma, extended in the direction of the coroation flow, analgous to the plume of smoke emitted in downwind direction from a smokestack. Such plumes were seen by {\em Voyager} 1 to be emitted by Titan. We find support for this proposition in published data from {\em Galileo} Plasma Science and Plasma Wave observations taken in the corotation wake of Europa and from magnetometer measurements reported from near the orbit, but away from Europa itself. This lends credence to the hypothesis that the plumes escaping from the ionosphere of Europa are wrapped around Jupiter by corotation, survive against dispersion for a fairly long time and are convected radially by magnetospheric motions. We present simple models of ionosphere aeronomy and plume acceleration and conclude that the plumes must consist of atomic oxygen ions flowing out, as observed, at subcorotational speed.
DE: 6028 Ionospheres--structure and dynamics
DE: 6218 Jovian satellites
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting