Reversal of the Fluctuation-Induced Transport during Low to High Transitions in the H-1 Heliac Plasma

Studies of turbulent transport in the H-1 heliac plasmas yield direct evidence of the reversal of the fluctuation-driven particle flux across the transition from low to high confinement mode. New types of transitions are characterized by significant fluctuation levels in the high confinement mode. The fluctuation-driven particle flux in the plasma core changes from outward to inward flow across this transition; this is accompanied by a peaking of the density profile and an increase in central ion temperature.