Kinetic Theory of Global n=1 Instabilities in Toroidal Plasmas

Abstract

The kinetic theory of the global n=1 instabilities of finite-pressure tokamak plasmas with circular cross-section is investigated in collisionless limit (m, n: poloidal and toroidal mode numbers). Wave-particle interactions and finite gyroradius effect are included. The radial-poloidal eigenmode equations are directly solved numerically. The m=1 internal/tearing mode, n=1 ballooning mode and m=2 tearing mode are identified with a fixed boundary condition. The m=1 internal mode turns out to be the collisionless tearing mode in low pressure regimes. The pressure driven ballooning mode is connected with the electrostatic-like ballooning mode. The toroidal coupling further stabilizes the m=2 tearing mode, which is destabilized by the parallel current and can be stabilized by coupling with drift branch. Analytical studies are made by using the energy integral.