Micro-tearing stability in Tokamaks

The resonant layer equations governing tearing and micro-tearing modes in toroidal geometry are formulated and solved for a plasma in the banana regime and for wavelengths in the intermediate collisionality range nu e < omega *e < nu e / epsilon . It is shown that stability of such tearing modes is determined by a competition between destabilizing trapped electron dissipation and stabilizing effects arising from ion magnetization and collisional broadening of the passing-electron Landau resonance. Analytic stability criteria are derived, but for realistic parameters these modes are predicted to be stable.