Abstract. Nonlinearly generated zonal flows are obtained from ion temperature gradient driven (ITG) modes and electromagnetic drift interchange modes. It is found that in general the flow is not important at the correlation lengths but gives an absorbing boundary for long wavelengths. For ITG modes, however, resonant excitation is found close to marginal stability. This may explain the strong effects of zonal flows seen in some nonlinear gyrokinetic simulations.
IAEA 2001