Modelling Europa's interaction with Jupiter's magnetosphere: Influence of plumes in Europa's atmosphere on the plasma environment

Abstract:

We study the influence of plumes in Europa's atmosphere on the interaction with Jupiter's magnetosphere and the plasma environment. We apply a three-dimensional magnetohydrodynamic (MHD) model, which includes plasma production and loss due to electron impact ionization and dissociative recombination, and electromagnetic induction in a subsurface water ocean.The model considers the magnetospheric and ionospheric electrons separately. We show that an atmospherical inhomogeneity, such as a plume, affects the plasma interaction in the way that a pronounced north-south asymmetry in the near and the Alfvénic far field develops. Furthermore, a “small Alfvén winglet” within Europa's Alfvén wing forms.

We also investigate if such signatures of atmospherical inhomogeneities are visible in magnetic field measurements of the Galileo magnetometer. In addition to our MHD model we apply an analytical approach based on the model by Saur et al. (2007) for our studies. We compare the model results with the observed magnetic field data from three flybys of Europa that occurred during the Alfvén wing crossing.