EDP Sciences
Free access
Issue A&A
Volume 450, Number 2, May I 2006
Page(s) 805 - 818
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20054099

A&A 450, 805-818 (2006)
DOI: 10.1051/0004-6361:20054099

The emergence of magnetic flux through a partially ionised solar atmosphere

J. E. Leake and T. D. Arber

Space and Astrophysics group, Dept. of Physics, University of Warwick, Gibbet Hill Road, CV4 7AL, Coventry, UK
    e-mail: J.E.Leake@warwick.ac.uk

(Received 24 August 2005 / Accepted 16 January 2006)

We present results from 2.5D numerical simulations of the emergence of magnetic flux from the upper convection zone through the photosphere and chromosphere into the corona. Certain regions of the solar atmosphere are at sufficiently low temperatures to be only partially ionised, in particular the lower chromosphere. This leads to Cowling resistivities orders of magnitude larger than the Coulomb values, and thus to anisotropic dissipation in Ohm's law. This also leads to localised low magnetic Reynolds numbers ( $R_{\rm m}<1$). We find that the rates of emergence of magnetic field are greatly increased by the partially ionised regions of the model atmosphere, and the resultant magnetic field is more diffuse. More importantly, the only currents associated with the magnetic field to emerge into the corona are aligned with the field, and thus the newly formed coronal field is force-free.

Key words: magnetohydrodynamics (MHD) -- magnetic fields -- plasmas -- Sun: atmosphere -- Sun: sunspots -- Sun: magnetic fields

© ESO 2006

What is OpenURL?

The OpenURL standard is a protocol for transmission of metadata describing the resource that you wish to access. An OpenURL link contains article metadata and directs it to the OpenURL server of your choice. The OpenURL server can provide access to the resource and also offer complementary services (specific search engine, export of references...). The OpenURL link can be generated by different means.
  • If your librarian has set up your subscription with an OpenURL resolver, OpenURL links appear automatically on the abstract pages.
  • You can define your own OpenURL resolver with your EDPS Account. In this case your choice will be given priority over that of your library.
  • You can use an add-on for your browser (Firefox or I.E.) to display OpenURL links on a page (see http://www.openly.com/openurlref/). You should disable this module if you wish to use the OpenURL server that you or your library have defined.

Editor-in-Chief: T. Forveille
Letters Editor-in-Chief: J. Alves
Managing Editor: C. Bertout

ISSN: 0004-6361 ; e-ISSN: 1432-0746
Frequency: 12 volumes per year
Published by: EDP Sciences

Mirror sites: CDS | EDP Sciences
  RSS feeds
© The European Southern Observatory (ESO)