Nonlinear Evolution of Collisionless and Semicollisional Tearing Modes

The evolution of a single tearing mode is investigated. The "collisionless" and "collisional" tearing modes nonlinearly evolve into the "semicollisional" regime where the dynamics of the "singular layer" are dominated by electron diffusion along the perturbed magnetic surfaces. The "semicollisional" mode grows algebraically in the nonlinear phase as in the "collisional" calculation of Rutherford.