Séminaire ISTerre

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Onset of convection in rotating spherical shells

lundi 4 novembre 2024 - 14h00

Ankit Barik - Johns Hopkins University (USA)
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Cores, magma oceans and atmospheres of planets can all be treated as fluids in rotating spherical shells. Thus, understanding thermal convection in such a system is of fundamental importance. In addition, understanding the linear problem is important to provide context of supercriticality for the fully nonlinear simulations. We use the eigenvalue code Kore to compute onset of convection and study the variation of critical parameters (critical Rayleigh number, wavenumber and drift frequency) as a function of rotation rate (Ekman number) and the radius ratio of inner boundary to outer boundary. This work has yielded a large dataset for the critical onset that we have made publicly available. We have also recently started extending this work to include magnetic fields in order to study the onset of magnetoconvection. Our results have yielded an array of interesting mode transitions as the magnetic field strength (Elsasser number) is varied.

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Equipe organisatrice : Géodynamo

Salle Dolomieu, Maison des Géosciences, 38400 Saint Martin d'Hères

Informations de visio :

https://univ-grenoble-alpes-fr.zoom.us/j/98438829344?pwd=iKr2vUvSyE3fCXh7JFzAS2b6bmFMc0.1