the present theoretical study. These issues will be discussed in the present study with an emphasis on the differences in the generation from the slab like and toroidal ITG mode branch.

The results are also interpreted in terms of quality of zonal flows i.e. the ratio of zonal flow growth rate and real frequency ($\Omega^{IM}/\Omega^{RE}$) [@a26]. The toroidally driven zonal flows exhibit a much larger ratio of growth rate and frequency compared to slab like driven flows (factor of three difference). The slab ITG generated zonal flow is only weakly dependent on $\eta_i$. Moreover, the quality of zonal flows is rather insensitive to $\eta_i$, in contrast to the results reported using the Wave Kinetic Equation (WKE) modeling. In many aspects the results found comparing the WKE modeling and the coherent mode coupling are qualitatively similar [@a20]. In the WKE modeling a strongly decreasing zonal flow quality with increasing $\eta_i$ was found [@a26], however in the present model the decrease of zonal flow quality is visible for larger $\eta_i$. It is also important to note that the difference in quality for slab like and toroidally generated zonal flows is approximately a factor of three. It is indicated that there is a 