The emergence of the plasma edge shear-flow layer has been recently shown to be consistent with second-order transition model coupling shear amplification by Reynolds stress and turbulence reduction by shear. A fundamental feature of second-order transitions in equilibrium thermodynamics is the divergence of the susceptibility near the critical point. In this paper, an experimental investigation is carried out to find out whether an analogous phenomenon takes place in the transition leading to the formation of the shear-flow layer in the TJ-II stellarator.
Formation of turbulent structures and the link to fluctuation driven sheared flows