F.Nabais, D. Borda, M. Mantsinen, M.F.F. Nave, S.E. Sharapov e os contributos do Joint European Torus-European Development Agreement

2005

In Joint European Torus (JET) [P. J. Lomas, Plasma Phys. Controled Fusion 31 , 1481 (1989)], discharges with ion cyclotron resonance heating only, low-density plasmas and high fast ions energy contents provided a scenario where fishbones behavior has been observed to be related with sawtooth activity: Crashes of monster sawteeth abruptly changed the type of observed fishbones from low-frequency fishbones [B. Coppi and F. Porcelli, Phys. Rev. Lett. 57 , 2272 (1986)] to high-frequency fishbones [L. Chen, R. White, and M. Rosenbluth, Phys. Rev. Lett. 52 , 1122 (1984)]. During periods between crashes, the type of observed fishbones gradually changed in the opposite way. Two new fishbones regimes have been observed in intermediate stages: Fishbones bursts covering both high and low frequencies and low amplitude bursts of both types occurring simultaneously. Both sawtooth and fishbones behavior have been explained using a variational formalism.