Cycling dynamics of the internal kink mode in non-linear two-fluid MHD simulations

The present work describes non-linear simulations leading to a description of diamagnetic thresholds for sawtooth cycles in tokamaks. Provided that a criterion of diamagnetic stabilization for a m/n=1/1 tearing is fulfilled, it is shown that diamagnetic effects alone can drive true sawteeth with complete magnetic reconnection in high temperature Ohmic plasmas with S~10^7-10^