Processing of Europas surface by its perturbed space environment

Europa, the smallest Galilean moon of Jupiter, possesses a saline subsurface ocean which is among the most promising sites to study ocean dynamics outside of Earth. The subsurface ocean may play a role in forming and modifying Europas diverse surface terrain, either via direct interaction (e.g., water-vapor plumes), or via protecting the surface from charged particle impacts through its induced magnetic field. In order to constrain the influence of induction in Europas conducting liquid water ocean on magnetospheric ion irradiation, as well as to determine which regions of the surface are most intensely processed via ion impacts, we model the spatial distribution of magnetospheric ion flux onto Europas surface. To do this, we combine the electromagnetic fields from a hybrid model (kinetic ions, fluid electrons) with a particle-tracing code in order to calculate the time-varying ion influx pattern over an entire synodic rotation of Jupiter. Our results show that Europas plasma interaction reduces ion flux onto Europa's orbital trailing surface by several orders of magnitude, while a significant number of the incident ions are deflected onto the surface of the leading hemisphere. Taking into account the deflection of energetic ions in the draped electromagnetic fields shifts the region of minimum energetic ion surface flux from Europas wakeside equator to its ramside equator. This generates an ``inverted bullseye" pattern of energetic ion flux centered at the trailing apex. This finding drastically alters the paradigm as to what regions across Europas surface feature surface ice which is least degraded via magnetospheric ion irradiation.