Stabilization of magnetohydrodynamic instabilities by force-free magnetic fields. I. Plane plasma layer.
Abstract
A marginal-stability analysis is applied to the stability problem of a plane plasma layer under the influence of gravity. Complete stability criteria are derived from the marginal equation of motion and it is shown that this method is equivalent to the application of the energy principle. Ideal magnetohydrodynamic instabilities, as occurring in simple plasma-vacuum systems, can be suppressed by replacing the vacuum by a force-free magnetic field, that is a field satisfying the relation ∇ × B = α B. Force-free fields of constant α are investigated in particular. By proper choice of α the gravitational instabilities, of nonlocal and of surface-layer type, are absent in a plane plasma layer supported from below by a horizontal force-free magnetic field. An appendix is devoted to a rigorous treatment of the influence of singular points of the marginal equation of motion on the stability analysis.
- Publication:
-
Physica
- Pub Date:
- 1971
- DOI:
- 10.1016/0031-8914(71)90127-3
- Bibcode:
- 1971Phy....53..412G