Seuren, Fleur ; Rekier, Jérémy ; Triana, Santiago Andrés ; Van Hoolst, Tim ; Dehant, Véronique

Invited talk presented at BPS General Scientific Meeting on 2023-05-17

Abstract: Stably stratified layers are widespread phenomena in geophysical and astrophysical applications. Formed by either the accumulation of light elements or a sub-adiabatic heat flux in the fluid parts of planetary or stellar cores, these stratified regions can have an immense influence on the environment in which they are generated. The weakness of Mercury’s magnetic field and the axisymmetry of Saturn’s magnetic field are for instance most likely caused by a strong stratified layer and oscillations in a stable layer at the top of the Earth’s core could be linked to observed variations in the length-of-day and magnetic field. Yet, many uncertainties about the causes and consequences of stratified layers remain and even regarding our own planet, the existence, extend and strength of the stable layer is still heavily debated. To address some of these open questions, we present in this study a linear numerical model, with applications to Mercury and the Earth, to investigate the fluid flow response in stably stratified layers and their impact on magnetic fields and rotation.

Funding: H2020/855677/GRACEFUL