Guervilly, C, Cardin, P and Schaeffer, N (2012) A dynamo driven by zonal jets at the upper surface: Applications to giant planets. Icarus, 218 (1). pp. 100-114. ISSN 0019-1035
Abstract
We present a dynamo mechanism arising from the presence of barotropically unstable zonal jet currents in a rotating spherical shell. The shear instability of the zonal flow develops in the form of a global Rossby mode, whose azimuthal wavenumber depends on the width of the zonal jets. We obtain self-sustained magnetic fields at magnetic Reynolds numbers greater than 10 3. We show that the propagation of the Rossby waves is crucial for dynamo action. The amplitude of the axisymmetric poloidal magnetic field depends on the wavenumber of the Rossby mode, and hence on the width of the zonal jets. We discuss the plausibility of this dynamo mechanism for generating the magnetic field of the giant planets. Our results suggest a possible link between the topology of the magnetic field and the profile of the zonal winds observed at the surface of the giant planets. For narrow Jupiter-like jets, the poloidal magnetic field is dominated by an axial dipole whereas for wide Neptune-like jets, the axisymmetric poloidal field is weak.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2011 Elsevier Inc. This is an author produced version of a paper published in Icarus. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Magnetic fields; Jupiter, Interior; Neptune, Interior; Rotational dynamics |
Dates: |
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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: | 25 Aug 2016 15:32 |
Last Modified: | 19 Feb 2018 19:50 |
Published Version: | http://dx.doi.org/10.1016/j.icarus.2011.11.014 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.icarus.2011.11.014 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:85500 |