Unravelling the dynamics of non-spherical planetary cores

The Earth's core is not only a remote internal layer as probed by seismology. It plays a crucial role in the Earth's dynamics, as it drives the large scale magnetic field measured at the surface, and affects our planet's rotation. So far, there are still mysteries that conventional models cannot unravel. For example, the dissipation in the Earth's and Moon's cores does not match the predictions of traditional models. Moreover, lunar paleomagnetism reveals a magnetic field in the Moon's early history far stronger than current convection-based dynamo models can account for. While most core flow simulations are based on the assumption of spherical geometry, it is now necessary to account non-spherical core-mantle boundary (CMB) in the models. Indeed, core-mantle couplings driven by non-spherical CMB shapes could hold the key to explain the aforementioned puzzling anomalies. However, accounting for the complex interplay of topography, magnetic forces, turbulence, rotation and buoyancy remains very challenging.

In this seminar, we will embark on a journey to present our on-going works considering both large-scale and small-scale deviations from the spherical symmetry. Using state-of-the-art theoretical, numerical and experimental techniques, I will show how core-mantle pressure coupling can provide new insights into planetary core dynamics.