Electrostatic transport reduction induced by flow shear modification in a reversed field pinch plasma

The E×B velocity and its shear have been modified in the edge of the RFX reversed field pinch experiment by a biasing experiment performed with electrodes inserted into the plasma. Causality between an increase in the E×B velocity shear and a decrease of the particle flux driven by electrostatic turbulence has been observed. The decrease of the particle flux has been found to be mainly due to a change of the relative phase between density and plasma potential fluctuations. The results confirm the role of sheared flow in transport suppression in reversed field pinches and show remarkable similarities with those found in other magnetic configurations.