A Threshold for Excitation of Neoclassical Tearing Modes
Authors: N. Gorelenkov, L. Zakharov, M. Gorelenkova
Stabilty criterion is obtained for neoclassical tearing modes. A finite amplitude of magnetic island is required for their excitation. In both collisional and collisionless regimes the threshold is determined by the ratio of the transversal and the parallel transport near the island, when the flattening of the pressure profile eliminates the bootstrap current. A number of TFTR supershots are compared with the theory. Both the stability condition and the critical island width are consistent with experimental data.