Modelling the temperature plateau in RFX-mod single-helical-axis (SHAx) states

The core region of high-current RFX-mod reversed field pinch plasmas spontaneously organizes into high-temperature helical flux tubes with almost intact magnetic surfaces. Accordingly, radial diffusion due to magnetic chaos is expected to be vanishingly small. Notwithstanding this, the temperature profile within these structures is flat, suggesting instead a substantial level of heat transport inside them. In this work we propose a rather simplified model of two-dimensional electrostatic turbulence valid in the low-magnetic chaos region and suggest that the effective homogenization of temperature may come from self-consistently generated vortical drift motion.