Parallel and perpendicular flows in the RFX-mod edge region

The relationship between edge flow features and local magnetic topology has been studied by means of ad hoc transient experiments, so that different plasma equilibria are compared within the same discharge, and of the edge flow monitor of helical magnetic islands in the RFX-mod Reversed Field Pinch experiment. The different components of the plasma flow characterizing the edge region and their shear are obtained by combining and comparing information provided by a noticeable set of edge diagnostics including insertable probes, toroidally distributed arrays of sensors and optical diagnostics. In particular a Gundestrup probe head is applied which allows obtaining information on both parallel and perpendicular Mach number. This probe head has been used with all the pins collecting floating potential signals and a model has been developed in order to reconstruct the flow.