Plasma flow in the outer region of the RFX reversed field pinch experiment

Abstract

Langmuir probes and collector samples have been exposed to the edge plasma in the RFX reversed field pinch experiment to investigate the plasma flow. Parallel and perpendicular drifts have been observed for primary ions and carbon impurities. Two models valid for a magnetized and an unmagnetized plasma have been applied and compared in order to derive the parallel and perpendicular drift velocities. The perpendicular flow is accounted for by the radial electric field and shows a velocity shear, consistent with the change in sign of the radial electric field in the edge region. The parallel flow increases going into the plasma