UC San Diego

Krommes' theory on dynamics of zonal flow in strong collisionless drift wave turbulence was analyzed. In the cold ion limit, the nonlinear growth rate generalized Kelvin-Helmholtz (GKH) mode and the equivalent expression, became identical, modulo notation for response function in the case when the background turbulence is isotropic. It was found that all of the substantive claims therein are incorrect. The results show that except for a factor of 1/2 in front of the diagonal Reynolds stress term in Kim and Diamond (KD) which should be corrected to unity, all other criticisms raised by Krommes are unfounded.