The effect of magnetic field on mean flow generation by rotating two-dimensional convection
American Astronomical Society
© 2016. The American Astronomical Society. All rights reserved.
Motivated by the significant interaction of convection, rotation, and magnetic field in many astrophysical objects, we investigate the interplay between large-scale flows driven by rotating convection and an imposed magnetic field. We utilize a simple model in two dimensions comprised of a plane layer that is rotating about an axis inclined to gravity. It is known that this setup can result in strong mean flows; we numerically examine the effect of an imposed horizontal magnetic field on such flows. We show that increasing the field strength in general suppresses the time-dependent mean flows, but in some cases it organizes them, leading to stronger time-averaged flows. Furthermore, we discuss the effect of the field on the correlations responsible for driving the flows and the competition between Reynolds and Maxwell stresses. A change in behavior is observed when the (fluid and magnetic) Prandtl numbers are decreased. In the smaller Prandtl number regime, it is shown that significant mean flows can persist even when the quenching of the overall flow velocity by the field is relatively strong.
Most of this work was carried out while I was a Ph.D student at the University of Leeds and I am grateful to the Science and Technology Facilities Council (STFC) for a Ph.D. studentship. This work was also supported by the European Research Council under ERC grant agreement No. 337705 (CHASM). Some of this work was undertaken on ARC1, part of the High Performance Computing facilities at the University of Leeds, UK, and some on the University of Exeter supercomputer, a DiRAC Facility jointly funded by STFC, the Large Facilities Capital Fund of BIS and the University of Exeter.
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