Free access article

A&A 468, 313-321 (2007)
DOI: 10.1051/0004-6361:20054495

Force-free magnetic field extrapolation for MHD boundary conditions in simulations of the solar atmosphere

A. Otto¹, J. Büchner², and B. Nikutowski<sup>2

1</sup>  Geophysical Institute, University of Alaska, Fairbanks, AK 99775, USA
    e-mail: ao@how.gi.alaska.edu
²  Max-Planck-Institut für Sonnensystemforschung, Max-Planck-Str. 2, 37191, Katlenburg-Lindau, Germany
    e-mail: buechner@linmpi.mpg.de

(Received 8 November 2005 / Accepted 14 February 2007)

Abstract
Context.In recent years the accuracy of magnetic field observations in the solar atmosphere has made considerable progress. Similar progress is being made in computer modeling of complex plasma systems and computer capabilities.
Aims.To consider observed solar magnetic field structure in numerical simulations a new extrapolation method for solar magnetic fields is used to incorporate such fields into three-dimensional MHD simulations
Methods.The simulation employs a new modified linear magnetic field extrapolation which is specifically designed to satisfy symmetry conditions which are generic to MHD models. The model domain includes photosphere, chromosphere, and corona.
Results.The new model is applied to several solar field configurations and results are compared to three-dimensional field structure from observations and another extrapolation method. The new model provides a simple and efficient method for the simulation of observed solar magnetic field structures by constructing a three-dimensional initial field that is consistent with symmetry boundary conditions of MHD simulations.

Key words: magnetohydrodynamics (MHD) -- Sun: magnetic fields -- Sun: corona -- methods: numerical -- plasmas

© ESO 2007

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