Reversed-field pinch research at Padua

Abstract

The Padua Reversed-Field Pinch research is reviewed with reference to three toroidal devices: ETA-BETA I which operated during 1974–1977, ETA-BETA II which is currently operating, and RFX which is being constructed. The paper summarizes in particular studies on impurity radiation losses, plasma density limits, and the properties of the mean and fluctuating magnetic field. The range of I/N values, limited by excessive radiation at high density and by excessive electron streaming and resistance anomaly at low density, is identified. Plasma confinement is discussed in comparison with the classical ion value and studies on magnetic field fluctuations indicate as a possible underlying process the diffusion in stochastic magnetic fields created by resistive MHD instabilities. The dependence of the plasma parameters on current and size is briefly discussed, together with the main motivations of future RFP experiments such as RFX.