Numerical investigation of MHD plasma instability by the method of projections on the unstable manifold

Abstract

In this paper, current profiles close to experimentally observed tokamak profiles are used to obtain a numerical solution of the system of MHD equations and to study the nonlinear interaction of resistive helical harmonics. We also determine the regions of strong and weak interaction of the tearing modes and provide a possible explanation of the observed relative stability of low-qa regimes, where qa is the helical stability coefficient. The proposed approach is based on the method of projections on the unstable manifold [5-7], which may be viewed as a variety of the separation of variables methods in nonlinear problems.