Rémy
Monville

researchgate gitlab ORCID scholar

Hi! I'm Rémy, a PhD student currently working at ISTerre lab in Grenoble on topographic core-mantle coupling within the ERC project "THEIA". I am interested in geophysical fluid dynamics, rotating flows and magnetohydrodynamics.

My PhD: Topographic coupling and wave dynamics in planetary cores

Earth and Moon's rotations are tracked accurately, and these data are inverted with rotation models, providing coupling between the liquid core and the solid layers (mantle, inner core). Despite these well-constrained values, the coupling mechanisms are still disputed. Interactions between planetary fluid layers and their solid boundaries are crucial aspects when studying flow dynamics and planetary motions. These couplings are not straightforward to calculate and can originate from pressure, gravity, viscous, or electromagnetic forces.
This topic has been widely explored in atmospheric and oceanic sciences but also has an interest for planetary interiors (e.g., liquid cores, magma oceans of exoplanets, subsurface oceans of icy moons). We thus need models combining rotation, stratification, and magnetic fields.
On Earth, it is a key aspect that is missing in forward models to explain the decadal change of the length of the day and the concomitant changes in core axial angular momentum, as well as the dissipation of the retrograde annual nutation. Here, we focus on the small-scale topographic effects caused by the flow in a stratified liquid core over a bumpy mantle, which gives rise to pressure forces or/and increases the electromagnetic coupling.
We develop a local Cartesian model based on plane wave perturbations, following the work of Jault (2020) and Glane & Buffett(2018). Our code ToCCo, relying on symbolic and arbitrary precision calculations, unlocks several limitations of previous approaches. Our “higher-order” solutions go beyond the forced wave linear regime, investigating non-linear effects and improving on previous results. With this new method, we explore a wide range of parameters and boundary conditions for arbitrary topography shapes. We also consider the spherical geometry, via spatial integration, that includes the lateral variations of the magnetic field and of the orientation of the rotation vector. To do so, we have implemented the “improved β-plane” approximation of Dellar (2011), for both the magnetic field and the rotation vector.

EXPERIENCES

EDUCATION

Grenoble Alpes University