A New MHD-Kinetic Approach to Europa's Atmosphere, Ionosphere and Interactionwith Jupiter's Magnetosphere

Europa's atmosphere is generated primarily by the surface sputtering of water-ice and H2O sublimation near the subsolar point Subsequent collisional interaction of the atmosphere with the co-rotating torus plasma results in a significant exchange of energy and momentum between them as well as Jupiter's magnetosphere via the resulting electric currents. In addition, solar radiation and reactive collisions with the torus plasma give rise to both new neutral species and water group ions. The interaction is strong enough to create an ionosphere with a density much larger than the background torus plasma, heat the atmosphere and significantly distort the background fields. We are in the process of developing a new model that combines a 3 D MHD model for the plasma interaction with Europa and its atmosphere and a 3 multi-species DSMC kinetic model that is an extension of the 2 D model of Smyth and Marconi (2006). While Europa's atmosphere has been modeled previously, this combined model will simulate the important mutual interaction of the magnetosphere and atmosphere f or the first time. We will present initial results with particular regard to the composition and structure of the atmosphere and ionosphere... Smyth, W.H. and M.L. Marconi (2006) Europa's Atmosphere Gas Tori andMagnetospheric Implications. Icarus 181, 510-526. Dr. Marconi acknowledges NASA grant NNX09AM62G and NAS HECC for computationalsupport.