Boundary Condition Studies in a Reversed-Field Pinch

Global discharge parameters have been studied in the Separatrix Test Experiment (STE)-2 reversed-field pinch (RFP) using circular and poloidal divertor RFP plasmas. An increase in the proximity of the resistive shell resulted in a reduction of the anomalous discharge resistance in both plasmas. In poloidal divertor discharges, heat flux measurements indicate that field-aligned flow of superthermal (fast) electrons exist both at the edge of the main plasma and in the divertor chamber, carrying significant amount of the heat flux in both regions. Implications of the results to the advanced RFP concept will be discussed.