The existence of a sub-surface ocean within europa was demonstrated by the galileo spacecrafts measurements of an induced dipole magnetic field. This field, produced by the time-variable background…

This is a $389,698.43 grant awarded by the National Aeronautics and Space Administration (NASA) to the University of Colorado for research into understanding the magnetic field of Jupiter's moon Europa and its subsurface ocean. The research aims to improve the interpretation of data from the Galileo spacecraft to better determine the properties of Europa's subsurface ocean, such as its thickness, depth, and salinity. The research will involve applying various plasma interaction models, including magnetohydrodynamic, multi-fluid, and hybrid simulations, to quantify the uncertainties and systematic errors introduced by the interaction between Jupiter's magnetosphere and Europa's ionosphere. This work is intended to enhance the analysis of data from planned future missions to Europa, such as the Europa Multiple Flyby Mission and the Jupiter Icy Moons Explorer. The contract does not have a set-aside designation.

The existence of a sub-surface ocean within europa was demonstrated by the galileo spacecrafts measurements of an induced dipole magnetic field. This field, produced by the time-variable background magnetic field from jupiter, is a result of currents flowing within an electrically conductive layer inside europa. Unfortunately, interpretation of the galileo results is complicated by the interaction between jupiters magnetosphere and europa and its ionosphere. This interaction also produces magnetic field perturbations which add uncertainty and systematic errors to the determination of the induced field. As a result, the galileo results show the existence of an ocean, but not its properties. With better understanding of the plasma interaction, a more precise determination of the induced field would be possible. This, in turn, would allow estimates of the sub-surface ocean's properties (e.g. thickness, depth and salinity.) at the present time, IT is unclear how sensitive such an analysis would be to the upstream plasma conditions, the structure of europas ionosphere, or the model techniques used to calculate the interaction magnetic field. Nor are the galileo results uncertainties and systematic errors wellquantified. We will investigate the impact of the plasma interaction on studies of the subsurface ocean by applying a variety of models. These will include MHD, multi-fluid and hybrid simulations. By systematically comparing the results for different upstream boundary conditions, treatments of the ionosphere and for different model assumptions, we will determine the sensitivity of the derived induced dipole to these factors. This will both improve our current understanding of europas interior, and enhance the results from planned missions (e.g. europa multiple flyby mission and jupiter ICY moons explorer) by indicating how precisely the upstream plasma and ionosphere should be understood to accurately determine the properties of the sub-surface ocean. Further, we will quantify the uncertainties and systematic errors the plasma interaction introduces into the analysis of galileo data.