Partial reconnection in the nonlinear internal kink mode

The effect of the electron pressure gradient in Ohm’s law on the nonlinear development of the internal kink mode is investigated. While pressure fluctuations have a destabilizing effect, the average pressure gradient giving rise to diamagnetic flows is stabilizing. If the latter is strong enough, it leads to saturation at finite island size. The relevance of the results for the sawtooth phenomenon in tokamak plasmas is discussed.