Plasma Interaction Signatures of Plumes at Europa

Abstract

We present a systematic modeling framework for the identification of water vapor plumes in plasma and magnetic field data from spacecraft flybys of Jupiter's moon Europa. In particular, we determine the degree to which different plume configurations can be obscured by the interaction of Jupiter's magnetospheric plasma with Europa's induced dipole field and its global atmosphere. Additionally we constrain the diagnostic potential of ion energy spectrograms to identify signatures of water vapor plumes in the thermal plasma environment of Europa.

We apply the hybrid model AIKEF (kinetic ions, fluid electrons) to investigate the effect of inhomogeneities in Europa's atmosphere (plumes) on the plasma interaction with the Jovian magnetosphere. To systematically assess the magnitude and structure of the perturbations associated with plume-plasma interaction at Europa, we vary the plume location across Europa's surface whilst considering different symmetric and asymmetric density profiles of the moon’s global atmosphere. To isolate the impact of a plume on Europa's magnetospheric environment, we also conduct model runs without any global atmosphere. To quantify the magnetic perturbations caused by plumes we analyze the magnetic field components along hypothetical spacecraft flybys and the Galileo E26 trajectory through a plume. In addition, the model output is used to generate synthetic time series for the count rates of the observable thermal ion population as a function of energy along several hypothetical spacecraft trajectories as well as for the Galileo E26 flyby. The results of these studies will facilitate the planning of synergistic measurements during upcoming missions to Europa.