Gyrokinetic particle-in-cell calculations of ion temperature gradient driven turbulence with parallel nonlinearity and strong flow corrections

Nonlinear gyrokinetic calculations have been performed with the three-dimensional, global, toroidal, nonlinear, particle-in-cell, delta-f or δf, massively parallel UCla-CANada (UCAN) code. Their purpose is to study the effects of the parallel nonlinearity and of strong (externally imposed) sheared flow corrections on ion temperature gradient (ITG) driven turbulence (ITGDT) in tokamaks. These calculations show that the strong flow corrections have a qualitative effect on the saturation level of the fluctuations and on the heat flux. The re-activated parallel nonlinearity, in combination with zonal flows, leads to a quantitative reduction in saturation level and heat flux. This reduction does however decrease with increasing system size.