The gravitational interchange instability for perpendicular density gradients
Abstract
The analouge of the Reyleigh-Taylor instability (the gravitational interchange mode) for an infinitely conducting, approximately one-dimensional plane plasma slab is examined when the gravitational acceleration g is taken to be perpendicular to the equalibrium density gradient δp0. In contrast with the ‘classical’ situation (where g is aligned with δp0), it is found for a current layer with Magnetic shear that there is no instability threshold equivalent to the ‘classical’ situation (where g is aligned with δp0), it is found for a current layer with magnetic shear that there is no instability threshold equivalent to the Suydam criterion: the mode is unstable for all values of |δp0|. In the weak shear limit the growth rate of the instability is shown to exhibit the familiar (g|δp0|/p0)img scaling characteristic of the gravitational interchange mode.
- Publication:
-
Journal of Plasma Physics
- Pub Date:
- February 1993
- DOI:
- 10.1017/S0022377800016846
- Bibcode:
- 1993JPlPh..49...85P