Partial reconnection in the sawtooth collapse

摘要

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 results are compared with recent measurements of the sawtooth collapse on the Textor tokamak and alternative concepts of the collapse are discussed. (author)