Magnetoplasma interactions with icy bodies

Abstract

Both the interaction between the Pluto-Charon system and the solar wind and Europa and the Jovian magnetosphere vary with system configuration. We use a global, three-dimensional, multifluid magnetohydrodynamic model (the Icy Bodies Model) to investigate Pluto's interaction with the solar wind, what role Pluto's companion Charon plays in this interaction, and mass loss from the system. We also use the Icy Bodies Model to explore how Europa's interaction with Jupiter's magnetosphere changes depending on its location within the magnetosphere and what contribution Europa's ionosphere makes to this interaction. In order to perform these simulations, we have modified the model to accommodate an arbitrary number of bodies within the system, to include dynamic, volumetric plasma source and loss terms based on realistic neutral atmospheric profiles, and to incorporate induced planetary magnetic dipoles. The three plasma sources implemented with the model are electron impact ionization, photoionization, and ion-neutral charge exchange. This last mechanism also acts as a loss term within the system because it involves ions recombining by stripping electrons from the neutral population. Simulations of the Pluto-Charon system have included three ion species (solar wind protons, Pluto-sourced heavy ions, and Charon-sourced heavy ions), while those of Europa have included two (Jovian magnetospheric plasma and Europan ionospheric singly ionized molecular oxygen). In addition to their utility in investigating system behavior, our simulations of the Pluto-Charon system provide context for flyby data returned by the SWAP and PEPSSI instruments on the New Horizons mission. Results are validated against previous modeling efforts, as well as this New Horizons data. Results of our exploratory Europa work are compared with other modeling studies.