On the stability of anisotopric field-reversed configurations

The stability of a class of anisotropic field-reversed configurations (FRCs) is studied using an extension of the energy principle. When a family of incompressible plasma displacements ξ satisfying B · (B · ∇ξ) = 0 with B the equilibrium magnetic field, is considered, the general result that the stability problem is equivalent to that of scalar pressure FRCs is obtained. The formalism allows us to predict the existence of global modes for toroidal mode number n greater than unity, with growth rates faster than for the n = 1 case, which corresponds to tilting instability. (Author)