English

Ejections of magnetic structures above a spherical wedge driven by a convective dynamo with differential rotation

Solar and Stellar Astrophysics 2012-10-16 v3

Abstract

We combine a convectively driven dynamo in a spherical shell with a nearly isothermal density-stratified cooling layer that mimics some aspects of a stellar corona to study the emergence and ejections of magnetic field structures. This approach is an extension of earlier models, where forced turbulence simulations were employed to generate magnetic fields. A spherical wedge is used which consists of a convection zone and an extended coronal region to 1.5\approx1.5 times the radius of the sphere. The wedge contains a quarter of the azimuthal extent of the sphere and 150\degr150\degr in latitude. The magnetic field is self-consistently generated by the turbulent motions due to convection beneath the surface. Magnetic fields are found to emerge at the surface and are ejected to the coronal part of the domain. These ejections occur at irregular intervals and are weaker than in earlier work. We tentatively associate these events with coronal mass ejections on the Sun, even though our model of the solar atmosphere is rather simplistic.

Keywords

Cite

@article{arxiv.1112.0505,
  title  = {Ejections of magnetic structures above a spherical wedge driven by a convective dynamo with differential rotation},
  author = {Jörn Warnecke and Petri J. Käpylä and Maarit. J. Mantere and Axel Brandenburg},
  journal= {arXiv preprint arXiv:1112.0505},
  year   = {2012}
}

Comments

25 pages, 17 figures, published in Solar Physics