Gyrokinetic Simulation of Global Turbulent Transport Properties in Tokamak Experiments
Authors: W.X. Wang, Z. Lin, W.M. Tang, W.W. Lee, S. Ethier, J.L.V. Lewandowski, G. Rewoldt, T.S. Hahm, and J. Manickam
Date of PPPL Report: January 2006
Submitted to: Physical Review E
A general geometry gyrokinetic model for particle simulation of plasma turbulence in tokamak experiments is described. It incorporates the comprehensive influence of non-circular cross section, realistic plasma profiles, plasma rotation, neoclassical (equilibrium) electric fields, and Coulomb collisions. An interesting result of global turbulence development in a shaped tokamak plasma is presented with regard to nonlinear turbulence spreading into the linearly stable region. The mutual interaction between turbulence and zonal flows in collisionless plasmas is studied with a focus on identifying possible nonlinear saturation mechanisms for zonal flows. A bursting temporal behavior with a period longer than the geodesic acoustic oscillation period is observed even in a collisionless system. Our simulation results suggest that the zonal flows can drive turbulence. However, this process is too weak to be an effective zonal flow saturation mechanism.