Hydromagnetic oscillations of a self-gravitating fluid spheroid

Abstract

The oscillations of a homogeneous, compressible, self gravitating fluid spheroid in static equilibrium with a poloidal magnetic field inside and a dipole type field outside are studied using the second order tensor virial equations. It is found that for small values of the eccentricity, the equilibrium model is dynamically stable provided the usual criterion of pulsative stability in the absence of a magnetic field (γ>4/3) is satisfied. The magnetic field removes the accidental degeneracy of the radial and the non-radial modes of oscillation which exists for γ=1.6 in the absence of a magnetic field.