MHD plasma stability in alternative toroidal systems and the local dispersion relation

The local dispersion relation obtained for an inhomogeneous anisotropic high-pressure plasma in the Chew-Goldberger-Low approximation is used to qualitatively study small-scale MHD plasma instabilities in alternative magnetic configurations in which the plasma compressibility plays a significant stabilizing role. It is established that it is important to satisfy the Bernstein-Kadomtsev condition in order to reduce the growth rate of the quasi-flute oscillations. Moderate plasma anisotropy is shown not to have a substantial destabilizing effect on the MHD plasma stability under the Bernstein-Kadomtsev condition in alternative systems. The situation in which the electron compressibility vanishes while the ion compressibility is nonzero is discussed; it is shown that, in this situation, the Bernstein-Kadomtsev condition becomes more stringent as the longitudinal wavenumber increases.