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Dynamo generated field emergence through recurrent plasmoid ejections

Published online by Cambridge University Press:  26 August 2011

Jörn Warnecke  and
Axel Brandenburg
Jörn Warnecke
Affiliation:
Nordita, AlbaNova University Center, Roslagstullsbacken 23, SE-10691 Stockholm, Sweden email: joern@nordita.org Department of Astronomy, AlbaNova University Center, Stockholm University, SE 10691 Stockholm, Sweden
Axel Brandenburg
Affiliation:
Nordita, AlbaNova University Center, Roslagstullsbacken 23, SE-10691 Stockholm, Sweden email: joern@nordita.org Department of Astronomy, AlbaNova University Center, Stockholm University, SE 10691 Stockholm, Sweden
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Abstract

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Magnetic buoyancy is believed to drive the transport of magnetic flux tubes from the convection zone to the surface of the Sun. The magnetic fields form twisted loop-like structures in the solar atmosphere. In this paper we use helical forcing to produce a large-scale dynamo-generated magnetic field, which rises even without magnetic buoyancy. A two layer system is used as computational domain where the upper part represents the solar atmosphere. Here, the evolution of the magnetic field is solved with the stress–and–relax method. Below this region a magnetic field is produced by a helical forcing function in the momentum equation, which leads to dynamo action. We find twisted magnetic fields emerging frequently to the outer layer, forming arch-like structures. In addition, recurrent plasmoid ejections can be found by looking at space–time diagrams of the magnetic field. Recent simulations in spherical coordinates show similar results.

Keywords

MHDSun: magnetic fieldsSun: coronal mass ejections (CMEs)turbulence
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 6 , Symposium S273: The Physics of Sun and Star Spots , August 2010 , pp. 256 - 260
Copyright
Copyright © International Astronomical Union 2011

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