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Solar Surface Magnetoconvection

Published online by Cambridge University Press:  26 May 2016

Robert F. Stein  and
Åke Nordlund
Robert F. Stein
Affiliation:
Physics and Astronomy Department, Michigan State University, East Lansing, MI 48824
Åke Nordlund
Affiliation:
Niels Bohr Institute for Astronomy, Physics, and Geophysics University of Copenhagen, DK

Abstract

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Magnetoconvection simulations on meso-granule and granule scales near the solar surface are used to study small scale dynamo activity, the emergence and disappearance of magnetic flux tubes, and the formation and evolution of micropores.

From weak seed fields, convective motions produce highly intermittent magnetic fields in the intergranular lanes which collect over the boundaries of the underlying meso-granular scale cells. Instances of both emerging magnetic flux loops and magnetic flux disappearing from the surface occur in the simulations. We show an example of a flux tube collapsing to kG field strength and discuss how the nature of flux disappearance can be investigated. Observed Stokes profiles of small magnetic structures are severely distorted by telescope diffraction and seeing.

Because of the strong stratification, there is little recycling of plasma and field in the surface layers. Recycling instead occurs by exchange with the deep layers of the convection zone. Plasma and field from the surface descend through the convection zone and rise again toward the surface. Because only a tiny fraction of plasma rising up from deep in the convection zone reaches the surface due to mass conservation, little of the magnetic energy resides in the near surface layers. Thus the dynamo acting on weak incoherent fields is global, rather than a local surface dynamo.

Type
Session C. Convection
Information
Symposium - International Astronomical Union , Volume 210: Modelling of Stellar Atmospheres , 2003 , pp. 169 - 180
Copyright
Copyright © Astronomical Society of the Pacific 2003 

References

Cattaneo, F. 1999, ApJ, 515, L39 Google Scholar
Dorch, S.B.F. & Nordlund, Å. 2001, A&A, 365, 562 Google Scholar
Emonet, T. & Cattaneo, F. 2001, ApJ, 560, L197 CrossRefGoogle Scholar
Hagenaar, H.J. 2001, ApJ, 555, 448 CrossRefGoogle Scholar
Harvey, K.L. & White, O.R. 1999, ApJ, 515, 812 Google Scholar
Nordlund, Å., Dorch, S.B.F., & Stein, R.F. 2000, J. of Astrophys. & Astron., 21, 307 Google Scholar
Stein, R.F. & Nordlund, Å. 2000, Solar Phys., 192, 91 CrossRefGoogle Scholar
Tobias, S.M., Brummell, N.H., Clune, T.L. & Toomre, J., 2001, ApJ, 549, 1183 Google Scholar