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Multilayered solar interface dynamos: from a Cartesian kinematic dynamo to a spherical dynamic dynamo

Published online by Cambridge University Press:  01 September 2007

Kit H. Chan
Affiliation:
Department of Mathematics, The University of Hong Kong, Pokfulam, Hong Kong email:mkhchan@hku.hk
Xinhao Liao
Affiliation:
Shanghai Astronomical Observatory, Shanghai 200030, China email:xhliao@shao.ac.cn
Keke Zhang
Affiliation:
Center for Geophysical & Astrophysical Fluid Dynamics, University of Exeter, UK email:kzhang@ex.ac.uk
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Abstract

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The existence of the solar tachocline, a thin differentially rotating layer at the base of the convection zone which is inferred from helioseismology, leads to the concept of an interface dynamo. The tachocline is magnetically coupled to the radiative interior and the overlying convection zone. A multilayered interface dynamo is required to describe the dynamo process involved. We first discuss a two-dimensional multilayered interface dynamo model in cartesian geometry consisting of four horizontal layers with different magnetic diffusivities magnetically coupled by the three sets of interface matching conditions for the generated magnetic field. Exact solutions of the coupled dynamo system are obtained in this model. We then discuss a fully three-dimensional and multi-layered spherical dynamic interface dynamo using a finite element method based on the three-dimensional tetrahedralization of the whole spherical system. The spherical dynamic interface dynamo also consists of four magnetically coupled zones. In the convection zone, the fully three-dimensional dynamic feedback of Lorentz forces is taken into account. It is shown that the dynamo is characterized by a strong toroidal magnetic field, selects dipolar symmetry and propagates equatorward.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2008

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