Stability of short wavelength tearing and twisting modes

摘要

The stability and mutual interaction of tearing and twisting modes in a torus is governed by matrices that generalize the well-known (Delta)(prime) stability index. The diagonal elements of these matrices determine the intrinsic stability of modes that reconnect the magnetic field at a single resonant surface. The off-diagonal elements indicate the strength of the coupling between the different modes. The author shows how the elements of these matrices can be evaluated, in the limit of short wavelength, from the free energy driving radially extended ballooning modes. The author applies the results by calculating the tearing and twisting (Delta)(prime) for a model high-beta equilibrium with circular flux surfaces.