Sawteeth, magnetic disturbances, and magnetic flux regeneration in the reversed-field pinch

Abstract

A comparison of experimental data and theoretical results is presented that may help to explain the underlying causes of the flux regeneration mechanism (‘‘dynamo’’) in the reversed-field pinch (RFP). Discrete events are seen on many diagnostic measurements which are coincident with observable increases in toroidal magnetic flux in discharges where the pinch parameter θ (θ≡Bθwall/〈Bφ〉) exceeds the value 1.6. By observing the relative timing and the θ dependence of these events as the discharge is returned to lower values of θ, a case may be made for associating the m=1 tearing mode with the RFP dynamo.