Role of Zonal Flow in Turbulent Transport Scalings
Transport scalings with respect to collisionality (nu_star) and device size (rho_star) are obtained from massively parallel gyrokinetic particle simulations of electrostatic toroidal ion-temperature-gradient (ITG) turbulence in the presence of zonal flows. Simulation results show that in weak turbulence regime ion thermal transport from electrostatic ITG turbulence depends on ion--ion collisions due to the neoclassical damping of self-generated zonal flows that regulate the turbulence. In strong turbulence regime, results from large-scale full torus simulations with device-size scans indicate that ITG transport can deviate from the gyro-Bohm scaling even with small scale fluctuation and isotropic spectra.
Published in 2000.