Volume 450, Number 2, May I 2006
|Page(s)||805 - 818|
|Published online||10 April 2006|
The emergence of magnetic flux through a partially ionised solar atmosphere
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
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 (). 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
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.