Short wavelength ion temperature gradient turbulence

The ion temperature gradient (ITG) mode in the high wavenumber regime (k(y)rho(s) > 1), referred to as short wavelength ion temperature gradient mode (SWITG) is studied using the nonlinear gyrokinetic electromagnetic code GENE. It is shown that, although the SWITG mode may be linearly more unstable than the standard long wavelength (k(y)rho(s) < 1) ITG mode, nonlinearly its contribution to the total thermal ion heat transport is found to be low. We interpret this as resulting from an increased zonal flow shearing effect on the SWITG mode suppression. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4759458]