Onset of inertial magnetoconvection in rotating fluid spheres

Simitev, R. D. and Busse, F. H. (2021) Onset of inertial magnetoconvection in rotating fluid spheres. Fluids, 6(1), 41. (doi: 10.3390/fluids6010041)

Abstract

The onset of convection in the form of magneto-inertial waves in a rotating fluid sphere permeated by a constant axial electric current is studied in this paper. Thermo-inertial convection is a distinctive flow regime on the border between rotating thermal convection and wave propagation. It occurs in astrophysical and geophysical contexts where self-sustained or external magnetic fields are commonly present. To investigate the onset of motion, a perturbation method is used here with an inviscid balance in the leading order and a buoyancy force acting against weak viscous dissipation in the next order of approximation. Analytical evaluation of constituent integral quantities is enabled by applying a Green’s function method for the exact solution of the heat equation following our earlier non-magnetic analysis. Results for the case of thermally infinitely conducting boundaries and for the case of nearly thermally insulating boundaries are obtained. In both cases, explicit expressions for the dependence of the Rayleigh number on the azimuthal wavenumber are derived in the limit of high thermal diffusivity. It is found that an imposed azimuthal magnetic field exerts a stabilizing influence on the onset of inertial convection and as a consequence magneto-inertial convection with azimuthal wave number of unity is generally preferred.

• Item Type: Articles
• Additional Information: The research of R.S. was funded by the Leverhulme Trust grant number RPG-2012-600.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Simitev, Professor Radostin

Creator Roles

Simitev, R.: Conceptualization, Formal analysis, Writing – original draft, Writing – review and editing

• Authors: Simitev, R. D., and Busse, F. H.
• College/School: College of Science and Engineering > School of Mathematics and Statistics > Mathematics
• Journal Name: Fluids
• Publisher: MDPI
• ISSN: 2311-5521
• ISSN (Online): 2311-5521
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Fluids 6(1):41
• Publisher Policy: Reproduced under a Creative Commons License