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Oscillatory migratory large-scale fields in mean-field and direct simulations

Published online by Cambridge University Press:  26 February 2010

Dhrubaditya Mitra ,
Reza Tavakol ,
Axel Brandenburg  and
Petri J. Käpylä
Dhrubaditya Mitra
Affiliation:
Astronomy Unit, School of Mathematical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK emails: dhruba.mitra@gmail.com; r.tavakol@qmul.ac.uk
Reza Tavakol
Affiliation:
Astronomy Unit, School of Mathematical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK emails: dhruba.mitra@gmail.com; r.tavakol@qmul.ac.uk
Axel Brandenburg
Affiliation:
NORDITA, Roslagstullsbacken 23, SE-10691 Stockholm, Sweden email: brandenb@nordita.org Department of Astronomy, Stockholm University, SE 10691 Stockholm, Sweden
Petri J. Käpylä
Affiliation:
NORDITA, Roslagstullsbacken 23, SE-10691 Stockholm, Sweden email: brandenb@nordita.org Observatory, Tähtitorninmäki (PO Box 14), FI-00014, University of Helsinki, Finland email: petri.kapyla@helsinki.fi
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Abstract

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We summarise recent results form direct numerical simulations of both non-rotating helically forced and rotating convection driven MHD equations in spherical wedge-shape domains. In the former, using perfect-conductor boundary conditions along the latitudinal boundaries we observe oscillations, polarity reversals and equatorward migration of the large-scale magnetic fields. In the latter we obtain angular velocity with cylindrical contours and large-scale magnetic field which shows oscillations, polarity reversals but poleward migration. The occurrence of these behviours in direct numerical simulations is clearly of interest. However the present models as they stand are not directly applicable to the solar dynamo problem. Nevertheless, they provide general insights into the operation of turbulent dynamos.

Keywords

MHDconvectionSun: magnetic fields
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 5 , Symposium S264: Solar and Stellar Variability: Impact on Earth and Planets , August 2009 , pp. 197 - 201
Copyright
Copyright © International Astronomical Union 2010

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