Effects of Rotating Magnetic Islands Driven by External Perturbation Fields in the TU-Heliac

A new method for rotating magnetic islands by external perturbation fields is proposed. In the experiments, perturbation fields were produced using four pairs of cusp field coil, in which alternating currents having a π/2 phase shift flowed. A phase shifter for the coil currents was designed and constructed. The phase difference in the floating potential signals measured using two Langmuir probes confirmed that the magnetic islands rotated in the counterclockwise direction (c/cw). The clockwise (cw) rotation was also observed in the plasma biased by the hot cathode electrode. These experimental results suggest the ability of producing plasma poloidal rotation driven by rotating islands.