EXPERIMENTAL INTERTWINEMENT OF RADIAL ELECTRIC FIELDS, FLUCTUATIONS AND TRANSPORT WITH DENSITY IN TJ-II PLASMAS

Traditionally, three transport regions have been considered in the TJ-II stellarator: the plasma core, where heat deposition physics seems to dominate transport and therefore the radial electric field; a confinement or bulk plasma region where collisional and, very likely, turbulent fluxes cooperate interlinked by radial electric fields and plasma rotation; and a third region near the edge where plasma-wall interaction and magnetic topology add new phenomena. This latter region, however, may still preserve the transport properties of the bulk region. We present our latest experimental results on edge fluctuations based on probe data and fast camera image analysis, as well as HIBP plasma potential and heat diffusion profiles in the bulk plasma, all of them tuned under a same experimental knob: the plasma density, which is indication of a close intertwinement of transport, turbulence and electric fields in stellarator plasmas.