EDP Sciences
Free access
Volume 391, Number 3, September I 2002
Page(s) 1155 - 1157
Section Physical and chemical processes
DOI http://dx.doi.org/10.1051/0004-6361:20020898

A&A 391, 1155-1157 (2002)
DOI: 10.1051/0004-6361:20020898

The onset of the magnetic buoyancy instability in partially ionized plasmas

G. T. Birk

Institute for Astronomy and Astrophysics, University of Munich, Germany Centre of Interdisciplinary Plasma Science, Garching, Germany

(Received 16 April 2002 / Accepted 4 June 2002 )

The magnetic buoyancy instability greatly influences the transport of magnetic flux in a variety of astrophysical objects. In this paper the stability of magnetic flux layers against magnetic buoyancy perturbations is studied for the first time for partially ionized plasmas. Different to the pure magnetohydrodynamic case, the onset of unstable modes depends not only on the field gradient but also on the field strength. Momentum transfer between the ionized and neutral plasma components leads to stabilization of at least short wavelengths or even all buoyancy modes.

Key words: instabilities -- sunspots -- galaxies: intergalactic medium -- galaxies: magnetic fields

© ESO 2002