Tuesday 29 Oct 2019: Stratification effects in anelastic convection
Dr. Laura Currie - University of Exeter
Harrison 170 13:30-15:30
Convection is important for transporting the heat generated in stars outwards. Coupled with rotation, it is also thought to play an important role in the generation of magnetic fields in stars. In addition, stellar interiors can by strongly stratified, (e.g., the Sun's convection zone contains about 14 density scale heights) and so understanding the interaction of compressibility effects and convection is key to describing many astrophysical systems. In this talk, I will consider the effects of stratification in convection via a series of two- and three-dimensional numerical simulations in a Cartesian domain under the anelastic approximation. In particular, I will explore the differences from the incompressible (Boussinesq) system that arise due to stratification. One key result from existing theory is that, for strongly stratified systems, the rate of dissipative heating can exceed the luminosity carried by convection. I will demonstrate that this is indeed the case in our simulations, and will consider the potential implications for the modelling of stellar interiors where modern standard evolutionary codes do not currently allow for dissipative heating. Time permitting, I will also show the flows generated in some of our simulations and discuss their potential suitability as candidates to sustain a large-scale magnetic field through dynamo action.