Effect of externally injected toroidal magnetic flux on the dynamo action in reversed-field pinch plasma

Summary form only given. Many experiments have shown that the dynamo action induced by MHD activities generates toroidal magnetic flux in reversed-field pinch (RFP) plasmas and that it is accompanied by the degradation of plasma confinement. Therefore, if the toroidal magnetic flux could be externally injected by other means, the confinement would be expected to be extremely improved. The transverse rotating magnetic field is one of the candidates for realizing the magnetic flux injection. because it can drive poloidal current without changing the current in the toroidal coil. In order to confirm the principle, a new device, TPX-R3, was constructed. The device is equipped with a pair of m=1/n=0 coils, which are directly wound on the discharge tube and are orthogonal to each other. In order to generate a transverse rotating magnetic field, high-frequency currents with phase difference of π/2 are supplied to each coil from capacitor banks. Standard RFP plasmas produced on TPX-R3 show sawtooth oscillations on various diagnostics