Icy Shell Dynamics of Ocean worlds and Mantle Convection of Terrestrial Planets
Understanding how tectonic surface motions on terrestrial planets are connected to internal dynamics is one of the major challenges in geoscience. Recently, large-scale, fully dynamic convection computations have brought the analysis of these links at realistic parameters within reach. We focus our research on understanding the processes that generate and maintain plate tectonics on an active planetary body. The icy satellites of Europa and Enceladus are also highly deformed with graben, ridges, and troughs, as well as active jets and geysers, suggesting their interiors are active to the present day, with implications for astrobiology. We have recently extended our work on terrestrial planets to the ice analog, trying to understand what processes allow convection on these icy worlds to be localized or global, and how convection can leave tell-tale traces of deformation scattered about the surface of these satellites. An additional avenue of research focuses on understanding how planets can migrate between tectonic regimes. Our team consists of Lukas Fuchs and Matthew Weller with Thorsten Becker, Luc Lavier, and Krista Soderlund.
Oceanography of Icy Satellites
Rotating convection theory predicts that Europa’s ocean may be characterized by quasi-3D convective turbulence. Krista Soderlund’s team developed the first global ocean convection model for Europa and found that the resulting ocean currents transmit the satellite’s internal heat most effectively in the equatorial region, which can directly influence the latitudinal thermo-compositional state of the ice shell. Given the limited knowledge of Europa’s ocean, current work is testing the sensitivity of this ocean convection hypothesis to uncertainties in geophysical properties. We are also investigating the ocean’s induction response to variations in the Jovian magnetic field and the influence of double diffusive convection. For more information, contact Krista Soderlund.
Internal Dynamics and Magnetism of Giant Planets
The multipolar dynamos of Uranus and Neptune provide a unique opportunity to test hypotheses for magnetic field generation. Krista Soderlund and collaborators have developed numerical models of turbulent convection in rotating spherical shells to test the hypothesis that poorly organized convective turbulence will generate ice giant-like dynamics. These Boussinesq models self-consistently drive east-west flows, internal heat fluxes, and magnetic fields that agree to first-order with those observed on Uranus and Neptune. However, the magnetic field strength and zonal wind speeds are overestimated in our models with constant electrical conductivity. Towards resolving this discrepancy, we hypothesize that incorporation of an electrically insulating outer molecular envelope will bring the magnetic field and zonal flows into quantitative agreement and are pursuing new simulations that include radial variations in electrical conductivity and background density stratification. For more information, contact Krista Soderlund.