Numerical and theoretical studies of turbulence and transport with E x B shear flows

A report is given of: (a) a substantial transport reduction by the turbulen ce driven E x B flows observed in three dimensional non-linear gyrokinetic simulations of microturbulence in magnetically confined toroidal plasmas, ( b) an analytical derivation of the effective shearing rate for the time dep endent E x B flow; (c) an interpretation of experimental data using linear gyrokinetic microinstability rotation models of E x B shear; (d) other deve lopments in gyrokinetic theory and simulation.