Shear flow reduces turbulent transport. Nonlinear saturation of the toroidal eigenmode just before transition to turbulence. Time evolution of ion density showing transition to turbulent state from nonlinear gyrokinetic simulation of tokamak plasma turbulence. Time sequences go left to right then top to bottom. Self-generated shear flows in nonlinear gyrokinetic simulations.
Top slices are ion density at early and later times.
Bottom slices show the electrostatic potential. Turbulence spreads radially in global nonlinear gyrokinetic simulations. The mode is very elongated in the direction following the magnetic field lines. Ion density perturbations in the poloidal plane from nonlinear gyrokinetic simulations of tokamak plasma turbulence. The top image is the linear phase and the bottom image is the saturated turbulent state.