LINEAR-STABILITY OF RESISTIVE MHD MODES - AXISYMMETRICAL TOROIDAL COMPUTATION OF THE OUTER REGION MATCHING DATA

The quest to determine accurately the stability of tearing and resisti ve interchange modes in two-dimensional toroidal geometry led to the d evelopment of the PEST-3 code, which is based on solving the singular, zero-frequency ideal MHD equation in the plasma bulk and determining the outer data Delta', Gamma', and A' needed to match the outer region solutions to those arising in the inner layers. No assumptions regard ing the aspect ratio, the number of rational surfaces or the pressure are made a priori. This approach is numerically less demanding than so lving the full set of resistive equations and has the major advantage of allowing for non-MHD theories of the non-ideal layers. Good converg ence is ensured by the variational Galerkin scheme used to compute the outer matching data. To validate the code, we focus on the growth rat e calculations of resistive kink modes which are reproduced in good ag reement with those obtained by the full resistive MHD code MARS. (C) 1 994 Academic Press, Inc.