A way to generate poloidal (zonal) flow in the dynamics of drift (Rossby) waves

The paper considers dynamics in the Charney-Hasegawa-Mima equation, basic to several different phenomena. In each of them, the generation of poloidal/zonal flow is important. The paper suggests a possibility to generate such flows (which can serve as transport barriers). Namely, one needs to create significant \emph{increment} and \emph{decrement} in neighborhoods of some wave vectors ${\bf k}_1$ and ${\bf k}_2$ (respectively) such that (1) $R_{{\bf k}_1}<R_{{\bf k}_2}$, where $R_{\bf k}$ is the spectral density of the extra invariant ($I=\int R_{\bf k} E_{\bf k} d{\bf k}$ is the extra invariant, with $E_{\bf k}$ being the energy spectrum), (2) $|{\bf k}_1|<|{\bf k}_2|$, and (3) ${\bf k}_1+{\bf k}_2$ is a poloidal/zonal wave vector. These three conditions define quite narrow region.