Radial electric field at the edge of RFX

In the RFX reversed field pinch experiment the radial electric field at the edge gives rise to a spontaneous double velocity shear layer. The velocity shear affects the properties of electrostatic turbulence and the related p article transport. Preliminary results of an experiment of edge biasing by electrodes are reported, showing that with electrode currents higher than 5 kA the radial electric field can be significantly modified.