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Flows and dynamos in a model of stellar radiative zones

Part of: 50 years of Mean Field Electrodynamics

Published online by Cambridge University Press:  25 June 2018

Radostin D. Simitev Open the ORCID record for Radostin D. Simitev [Opens in a new window]  and
Friedrich H. Busse
Radostin D. Simitev*
Affiliation:
School of Mathematics and Statistics, University of Glasgow, Glasgow G12 8QQ, UK
Friedrich H. Busse
Affiliation:
Institute of Physics, University of Bayreuth, Bayreuth 95440, Germany
*
†Email address for correspondence: [email protected]
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Abstract

Stellar radiative zones are typically assumed to be motionless in standard models of stellar structure but there is sound theoretical and observational evidence that this cannot be the case. We investigate by direct numerical simulations a three-dimensional and time-dependent model of stellar radiation zones consisting of an electrically conductive and stably stratified anelastic fluid confined to a rotating spherical shell and driven by a baroclinic torque. As the baroclinic driving is gradually increased a sequence of transitions from an axisymmetric and equatorially symmetric time-independent flow to flows with a strong poloidal component and lesser symmetry are found. It is shown that all flow regimes characterised by significant non-axisymmetric components are capable of generating a self-sustained magnetic field. As the value of the Prandtl number is decreased and the value of the Ekman number is decreased, flows become strongly time dependent with progressively complex spatial structure and dynamos can be generated at lower values of the magnetic Prandtl number.

Keywords

astrophysical plasmasplasma flows
Type
Research Article
Information
Journal of Plasma Physics , Volume 84 , Issue 3 , June 2018 , 735840308
Copyright
© Cambridge University Press 2018 

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