Instability of the Equipartition State in a Fluid Sphere.
Abstract
Perturbations of a toroidal equipartition state in a homogeneous, compressible sphere are investigated in the tensor virial approximation. The equipartition state mixes the radial pulsation and the lowestorder Kelvin oscillation of the sphere. For any fluid, the sphere is unstable if the maguetic energy exceeds a critical value. This value depends upon T, the ratio of specific heats of the fluid, but in no case is it larger than ` of the gravitational energy of the sphere. For T < , it is the radial mode which becomes unstable: for > , it is the Kelvin mode. For = , neither of the lowest modes reduces to either the radial mode or the Kelvin mode in the limit of small . The results are examined in the limit of large (nearly incompressible fluid).
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 1964
- DOI:
- 10.1086/147912
- Bibcode:
- 1964ApJ...140..257K