Collaborative Research: Planetary Magnetism and Thermochemical Evolution

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AST-090206/0909171Schubert/RaymondThis research will study the coupled thermochemical-magnetic evolution of Mercury, Mars, the Moon, and Ganymede. In one project, a numerical dynamo code, specifically written to operate efficiently on massively parallel computers, will simulate the magnetic fields of these bodies at many times during their evolution. The calculations will be used along with observations of intrinsic magnetic fields and crustal magnetization to understand better the thermochemical evolution of solid planets. Joint inversions of crustal gravity and magnetic anomalies will also be undertaken for the Moon and Mars using multiple data sets (magnetic field, gravity, topography and geology). The density and magnetization distributions and their correlation, together with geologic and topographic data, will be used to infer the processes that modified the crust, e.g., magnetization or demagnetization by magmatic intrusions.These studies will contribute in a fundamental way to our understanding of how terrestrial planets and moons evolve through geologic time and how they produce magnetic fields through dynamo action in their cores. The investigations will also help determine how the crusts on the Moon and Mars were magnetized. By studying how dynamos can operate under the different physical conditions encountered in the cases of Mercury and Ganymede and in early Mars and the Moon we will better understand how the Earth generates its magnetic field.These activities will have application to many scientific disciplines, including planetary science, geophysics, geophysical fluid dynamics, and geomagnetism. The project will support participation by two research scientists and the training of a Ph.D. student in the planetary sciences, all of whom are members of an underrepresented group. The astronomical community will also benefit from the planned release of the modeling code developed here.