Volume 488, Number 1, September II 2008
|Page(s)||1 - 7|
|Published online||01 July 2008|
Non-axisymmetric instability of axisymmetric magnetic fields
INAF, Osservatorio Astrofisico di Catania, Via S.Sofia 78, 95123 Catania, Italy e-mail: email@example.com
2 INFN, Sezione di Catania, Via S.Sofia 72, 95123 Catania, Italy
3 A.F.Ioffe Institute of Physics and Technology and Isaac Newton Institute of Chile, Branch in St. Petersburg, 194021 St. Petersburg, Russia
Accepted: 10 April 2008
Context. The MHD instabilities can generate complex field topologies even if the initial field configuration is a very simple one.
Aims. We consider the stability properties of magnetic configurations containing a toroidal and an axial field. In this paper, we concentrate mainly on the behavior of non-axisymmetric perturbations in axisymmetric magnetic configurations.
Methods. The stability is treated by a linear analysis of ideal MHD equations.
Results. In the presence of an axial field, it is shown that the instability can occur for a wide range of the azimuthal wavenumber m, and its growth rate increases with increasing m. At given m, the growth rate is at its maximum for perturbations with the axial wave-vector that makes the Alfvén frequency approximately vanishing. We argue that the instability of magnetic configurations in the ideal MHD can typically be dominated by perturbations with very short azimuthal and axial wavelengths.
Key words: magnetohydrodynamics (MHD) / instabilities / stars: magnetic fields
© ESO, 2008
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.