WT-3トカマクにおける電子サイクロトロン加熱によるm=2ティアリングモードの抑制

抄録

On the WT-3 tokamak, stationary m=2 tearing mode was observed on magnetic probe signals in an ohmic heating (OH) plasma. Soft x-ray measurement showed that the m=1 mode and the sawtooth oscillation coexisted with the m=2 mode in this plasma. The frequency of the m=1 mode was the same as that of the m=2 mode. The effect of electron cyclotron heating (ECH) on the m=2 mode was investigated. We have found that both m=1 and m=2 modes were suppressed by applying ECH at the q=1 surface as well as at the q=2 surface. The amplitude of the m=1 and m=2 modes decreased as the power of ECH increased and both m=1 and m=2 modes were completely suppressed when the power of ECH was nearly equal to that of the target OH plasma. The experimental results showed that the m=1 and m=2 modes were tightly coupled to each other. In the case of the application of ECH at the q=1 surface, the central electron temperature increased significantly, suggesting that the confinement characteristics of the plasma was improved probably due to the suppression of the overlapping of the m=1 and m=2 modes by ECH.