ISTerre seminar

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Modelling double diffusive staircases in one dimension

Tuesday 15 October 2024 - 11h00

Paul Pruzina - Isaac Newton Institute and DAMTP (both University of Cambridge) - now at ISTerre
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Double diffusive convection occurs when the density of a fluid is affected by two scalars that diffuse at different rates. A destabilising gradient of salt (or other solute) in a thermally stable fluid can lead to instability, even if the overall density gradient is stable to convection. Past this initial instability there is a rich variety of behaviours, including the spontaneous formation of density staircases - systems of well-mixed turbulent layers separated by sharp interfaces. Such staircases are common throughout the Earth's oceans, and also expected to exist in the stratified zones of stars and giant planets. Despite a long history of study, the mechanism governing the formation and subsequent evolution of staircases is poorly understood. With staircases existing on very large horizontal scales, one-dimensional models provide an in-road to the physics. I present a summary of the current leading theory, and describe a model for staircase evolution, from the initial linear instability to their long-time state.

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Organizing team : Géodynamo

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

Informations de visio :

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