Generalized nonlinear Schrodinger equation as a model for turbulence, collapse, and inverse cascade.

A two-dimensional generalized cubic nonlinear Schroedinger equation with complex coefficients for the group dispersion and nonlinear terms is used to investigate the evolution of a finite-amplitude localized initial perturbation. It is found that modulation of the latter can lead to sideband formation, wave condensation, collapse, turbulence, and inverse energy cascade, although not all together and not in that order.