Magnetospheric ion bombardment of Europa’s surface

Jupiter’s moon Europa is embedded deep within the Jovian magnetosphere and is thus exposed to intense bombardment by charged particles, from thermal plasma to more energetic particles at radiation belt energies. Examples of radiation-induced surface alteration include sputtering, radiolysis and grain sintering; processes that are capable of significantly altering the physical properties of surface material. An accurate understanding of charged particle weathering at Europa is crucial to the interpretation of in-situ and remote observations carried out by past and future missions, as well as ground-based and space-based telescopes.

The access, and thus flux, of magnetospheric particles to the surface is highly non-uniform and is a consequence of both fundamental particle motions in Jupiter’s magnetosphere as well as local electromagnetic perturbations near the moon.

We have investigated the flux of magnetospheric ions at Europa’s surface by carrying out single-particle tracing within realistic electromagnetic fields from multi-fluid magnetohydrodynamic simulations of the moon’s interaction with Jupiter’s magnetosphere. Similar to previous studies, we find that magnetic field line draping and pile-up leads to shielding and drastically reduced flux at low latitudes across Europa’s trailing (upstream) hemisphere. Furthermore, we find that magnetic induction within Europa’s sub-surface ocean leads to additional shielding when the moon is located at high magnetic latitudes. Overall, we find that high latitude regions on Europa receive the largest flux of magnetospheric ions.