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' 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. A method is presented for evaluating the elements of these matrices, in the limit of short wavelength, from the free energy driving radially extended ballooning modes. This method is applied to calculate the tearing and twisting Delta' for a model high-beta equilibrium with circular flux surfaces. (C) 1999 American Institute of Physics. [S1070-664X(99)03004-9]. [References: 34]