Global characteristics of zonal flows generated by ion temperature gradient driven turbulence in tokamak plasmas

Miyato, Naoaki; Kishimoto, Yasuaki; Li, J.

Global structure of zonal flows driven by ion temperature gradient driven turbulence in tokamak plasmas is investigated using a global electromagnetic Landau fluid code. Characteristics of the coupled system of the zonal flows and the turbulence change with the safety factor . In a low region stationary zonal flows are excited and suppress the turbulence effectively. Coupling between zonal flows and poloidally asymmetric pressure perturbations via a geodesic curvature makes the zonal flows oscillatory in a high region. Also we identify energy transfer from the zonal flows to the turbulence via the poloidally asymmetric pressure perturbations in the high region. Therefore in the high region the zonal flows cannot quench the turbulet transport completely.