Inverse cascade in Charney-Hasegawa-Mima turbulence

The inverse energy cascade in the Charney-Hasegawa-Mima turbulence is investigated. The Kolmogorov law for the third-order velocity structure function is derived and shown to be independent of the parameter lambda, at variance with the energy spectrum, as shown by high-resolution direct numerical simulations. In the asymptotic limit of strong rotation, lambda -->infinity, the Kolmogorov constant is found to be C-lambda similar or equal to 11 while coherent vortices are observed to form at a dynamical scale which slowly grows with time. These vortices form an almost quenched pattern and induce a strong deviation form Gaussianity in the velocity field.