Gerick, F, Jault, D, Noir, J et al. (1 more author) (2020) Pressure torque of torsional Alfvén modes acting on an ellipsoidal mantle. Geophysical Journal International, 222 (1). pp. 338-351. ISSN 0956-540X
Abstract
We investigate the pressure torque between the fluid core and the solid mantle arising from magnetohydrodynamic modes in a rapidly rotating planetary core. A two-dimensional reduced model of the core fluid dynamics is developed to account for the non-spherical core-mantle boundary. The simplification of such a quasi-geostrophic model rests on the assumption of invariance of the equatorial components of the fluid velocity along the rotation axis. We use this model to investigate and quantify the axial torques of linear modes, focusing on the torsional Alfvén modes (TM) in an ellipsoid. We verify that the periods of these modes do not depend on the rotation frequency. Furthermore, they possess angular momentum resulting in a net pressure torque acting on the mantle. This torque scales linearly with the equatorial ellipticity. We estimate that for the TM calculated here topographic coupling to the mantle is too weak to account for the variations in the Earth’s length-of-day.
Metadata
Item Type: | Article |
---|---|
Authors/Creators: |
|
Copyright, Publisher and Additional Information: | © The Author(s) 2020. Published by Oxford University Press on behalf of The Royal Astronomical Society. This article has been accepted for publication in Geophysical Journal International © The Author(s) 2020. Published by Oxford University Press on behalf of The Royal Astronomical Society. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Keywords: | Core; Earth rotation variations; Numerical modelling |
Dates: |
|
Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mathematics (Leeds) > Applied Mathematics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 16 Apr 2020 11:53 |
Last Modified: | 29 Jun 2020 15:32 |
Status: | Published |
Publisher: | Oxford University Press (OUP) |
Identification Number: | 10.1093/gji/ggaa166 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:159435 |