Livermore, PW, Jackson, A and Hollerbach, R (2013) Electromagnetically driven westward drift and inner-core superrotation in Earth’s core. Proceedings of the National Academy of Sciences of the United States of America, 110 (40).
Abstract
A 3D numerical model of the earth’s core with a viscosity two orders of magnitude lower than the state of the art suggests a link between the observed westward drift of the magnetic field and superrotation of the inner core. In our model, the axial electromagnetic torque has a dominant influence only at the surface and in the deepest reaches of the core, where it respectively drives a broad westward flow rising to an axisymmetric equatorial jet and imparts an eastward-directed torque on the solid inner core. Subtle changes in the structure of the internal magnetic field may alter not just the magnitude but the direction of these torques. This not only suggests that the quasi-oscillatory nature of inner-core superrotation [Tkalčić H, Young M, Bodin T, Ngo S, Sambridge M (2013) The shuffling rotation of the earth’s inner core revealed by earthquake doublets. Nat Geosci 6:497–502.] may be driven by decadal changes in the magnetic field, but further that historical periods in which the field exhibited eastward drift were contemporaneous with a westward inner-core rotation. The model further indicates a strong internal shear layer on the tangent cylinder that may be a source of torsional waves inside the core.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | (c) 2013, National Academy of Sciences. This is an author produced version of a paper published in Proceedings of the National Academy of Sciences of the United States of America. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | geomagnetism; geodynamo |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mathematics (Leeds) > Applied Mathematics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 16 Sep 2014 10:59 |
Last Modified: | 16 Nov 2016 13:20 |
Published Version: | http://dx.doi.org/10.1073/pnas.1307825110 |
Status: | Published |
Publisher: | National Academy of Sciences |
Identification Number: | 10.1073/pnas.1307825110 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:80169 |