Stabilization of turbulence and enhanced particle confinement by velocity shear

Positive radial electric fields have been applied to the edge of the TEXTOR -94 tokamak plasma to create an (E) over right arrow x (B) over right arrow driven plasma flow. We observe partial stabilization of the electrostatic turbulence, at modest shear. After bifurcation of the radial electric field , to a high velocity shear condition, high poloidal plasma rotation (12-20 km/s) generated by (E) over right arrow x (B) over right arrow forces is in ferred from probe measurements of the phase velocity of the turbulence and from spectroscopy. The turbulent radial transport is quenched in a narrow r egion (similar to 1.5 cm) where the double shear layer is localized and the electric field is large. Hence stabilization of turbulence by (E) over rig ht arrow x (B) over right arrow sheer flow is clearly demonstrated. The res ult of the particle transport reduction is an increase in the global partic le confinement time tau(p) by a factor of 2 and in the global energy confin ement tim tau(E) by 20%. We thus show clearly that turbulent radial particl e transport accounts for much of the total radial transport.