Asymmetric Flux Generation and Its Relaxation in Reversed Field Pinch

Abstract

The toroidally asymmetric flux enhancement (“dynamo effect”) and the axisymmetrization of the enhanced fluxes that follows in the setting up phase of Reversed Field Pinch are investigated on the STP-3(M) device. A rapid increase in the toroidal flux generated by the dynamo effect is first observed near the poloidal and toroidal current feeders. Then, this inhomogeneity of the flux propagates toroidally towards the plasma current. The axisymmetrization of the flux is attained just after the maximum of plasma current. The MHD activities decrease significantly after this axisymmetrization and the quiescent period is obtained.