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A&A 481, L5-L8 (2008)
DOI: 10.1051/0004-6361:20078998
Letter
Strong horizontal photospheric magnetic field in a surface dynamo simulation
M. Schüssler1 and A. Vögler21 Max-Planck-Institut für Sonnensystemforschung, Max-Planck-Strasse 2, 37191 Katlenburg-Lindau, Germany
e-mail: schuessler@mps.mpg.de
2 Sterrekundig Instituut, Utrecht University, Postbus 80 000, 3508 TA Utrecht, The Netherlands
e-mail: A.Voegler@astro.uu.nl
(Received 5 November 2007 / Accepted 6 January 2008)
Abstract
Context.Observations with the Hinode spectro-polarimeter have revealed
strong horizontal internetwork magnetic fields in the quiet solar
photosphere.
Aims.We aim to interpret the observations with results from
numerical simulations.
Methods.Radiative MHD simulations of dynamo action by near-surface
convection are analyzed with respect to the relation between vertical
and horizontal magnetic field components.
Results.The dynamo-generated fields show a clear dominance of the horizontal
field in the height range where the spectral lines used for the Hinode observations are formed. The ratio between the averaged
horizontal and vertical field components is consistent with the values
derived from the observations. This behavior results from the
intermittent nature of the dynamo field with polarity mixing on small
scales in the surface layers.
Conclusions.Our results provide further evidence that local near-surface dynamo
action contributes significantly to the solar internetwork fields.
Key words: Sun: magnetic fields -- Sun: photosphere -- magnetohydrodynamics (MHD)
© ESO 2008