Presentation #521.04 in the session Dark Sea: Icy ocean worlds and astrobiology (iPosters).
To support future missions to Europa, such as Europa Clipper and JUICE, physics-based models for Europa’s neutral gas are in demand. Various physical and chemical processes need to be included in such models. H2O and O2 are the major sputtered species produced by the bombardment of magnetospheric ions and electrons on the icy surface of Europa. The dissociated products of H2O and O2 undergo chemical reactions further to produce other daughter species in the exosphere. In addition to sputtering, sublimation of water ice is another mechanism for supplying H2O to the atmosphere. Photochemical and electron impact reactions are the primary loss mechanism of H2O and other molecular species and the source mechanism of OH, O, and H. This work presents a new 3D model of Europa’s tenuous atmosphere. We have used the Direct Monte Carlo Simulation (DSMC) method to simulate Europa’s atmosphere under conditions ranging from the collisionless (Kn ≫ 1) to the quasi-collisional one (Kn ~ 0.1). The results of the MHD modeling of Jupiter’s magnetosphere are used to determine the plasma condition in the vicinity of Europa, and to compute the sputtering and electron impact reaction rates. The project aims to investigate the plasma’s effects on the exosphere.
Support for this work is provided by NASA grant 80NSSC20K0854 from the Solar System Workings program