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Ice Shell Convection

I have recently branched out into geophysics and solar system research. Jupiter's moon Europa is a likely place to find extraterrestrial life in the Solar System, and NASA has now approved the Europa Clipper mission, currently in development. I have been working on numerical models for the convecting ice shell of Europa that links the surface to the hidden ocean. A paper on ice shell convection on Europa, modeled with CitComS, and led by a student, Leonardo Sattler-Cassara, is currently under review.

We solve the equations of Stokes flow with ice rheology, in a 2D grid ranging from the top of the subsurface ocean to the surface of the moon. The incompressibility condition is satisfied by defining a streamfunction, and solving the elliptic problem iteratively via successive over-relaxation. Temperature evolution is calculated via a high-order non-conservative finite-difference stencil, as in the Pencil Code.

The parameter A is related to ice grain size and is roughly equivalent to the order of magnitude change in viscosity from top to bottom. The Reynolds number is very small, yet the Rayleigh number is very large (~2e7), so convection is the dominant mechanism of heat transfer. In some models, buoyant warm ice reaches the surface, leading to topography of ~100m, consistent with the terrain's morphology observed by Voyager and Galileo. Video and simulation by Leonardo Sattler, M.Sc. from UFRJ.

Publications:
Sattler-Cassara & Lyra, Icarus, in review.
Sattler-Cassara, M.Sc. thesis, Federal University of Rio de Janeiro (2017).
Sattler-Cassara, B.Sc. thesis, Federal University of Rio de Janeiro (2014).