Towards a diffusion-free regime in models of stellar and planetary convection: theory and simulations

Laura Currie (University of Durham)

Wednesday 10th December 15:00-16:00
Maths 311B

Abstract

The evolution of stars and planets is governed by turbulent flows in their interiors, which transport heat and generate magnetic fields. These flows are often convective, and their dynamics are strongly influenced by rotation and density stratification. Modelling such convection remains a central challenge in astrophysics due to the extreme parameter regimes involved: microscopic diffusivities in stars and planets are many orders of magnitude smaller than those accessible in simulations or experiments. In the astrophysical limit of vanishing diffusivities, the turbulent flow is expected to become “diffusion-free”, meaning its large-scale properties are independent of the microscopic transport coefficients. This assumption underlies Mixing Length Theory (MLT), which is widely used to model stellar and planetary convection. However, standard MLT neglects key physical effects such as rotation. In this talk, I will present an extension of MLT that includes rotation and compare its predictions with results from numerical simulations of rotating convection. I will also describe an idealised simulation framework that incorporates internal heating and cooling, designed to more directly approach the diffusion-free regime by bypassing traditional boundary-driven setups. 

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