A&A 423, L37-L40 (2004)
DOI: 10.1051/0004-6361:200400034
Letter
Non-axisymmetric spherical interface dynamos
K. H. Chan1, X. Liao2, K. Zhang1 and C. A. Jones11 Department of Mathematical Sciences, Laver Building, University of Exeter, EX4 4QE, UK
e-mail: kzhang@ex.ac.uk
2 Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, PR China
(Received 4 June 2004 / Accepted 12 July 2004)
Abstract
A fully three-dimensional, nonlinear, time-dependent spherical
interface dynamo with a solar-like internal differential rotation
and a single-cell meridional circulation is investigated. There
are four regions in our interface dynamo model: a uniformly
rotating core, a thin differentially rotating tachocline, a
turbulent convection zone and a nearly insulating exterior. The
different regions are coupled by the electric and magnetic
matching conditions at the interfaces. For the first time,
non-axisymmetric spherical nonlinear interface dynamos are found.
When the magnetic Reynolds number based on the differential
rotation is small or when the effect of the meridional circulation
is substantial, we show that the spherical interface dynamos are
non-axisymmetric even though the
-distribution,
differential rotation and meridional circulation are all
axisymmetric. Implication of the results for the solar dynamo is
discussed.
Key words: magnetohydrodynamics -- Sun: interior -- Sun: magnetic field
© ESO 2004

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