THE GRAVITATIONAL INTERCHANGE INSTABILITY
The analogue of the Rayleigh-Taylor instability (gravitational interchange mode) for an infinitely conducting, approximately one-dimensional plane plasma slab is examined when the gravitational acceleration g is supposed to be perpendicular to the equilibrium density gradient nablarho-"rm o". It is found that, in contrast with the classical situation (where g is aligned with nablarho-"rm o"), there is no preferred direction for instability of either g or nablarho-"rm o". Furthermore, for a current layer with magnetic shear, the mode is unstable for all values of vertnablarho-"rm o"vert : there is no instability threshold equivalent to the Suydam criterion for the classical gravitational interchange mode. The characteristic growth rate of the instability is given by omega-"rm G"/sqrt2, where omega-"rm G" simeq ("rm g"vertnablarho-"rm o"vert/rho-"rm o") "1over2" denotes the characteristic growth rate of the Rayleigh-Taylor instability, together with a small oscillatory frequency.
Bibliographic Reference: REPORT EUR-CEA-FC-1314-EN-1987, AVAILABILITY: CEA/CEN, CADARACHE, F
Record Number: 1989126088200 / Last updated on: 1989-05-01
Available languages: en