Waves statistics for generalized one-dimensional Nonlinear Schrodinger Equation with saturated nonlinearity

Abstract

We measure spectra, spatial correlation functions and probability density functions (PDFs) for waves amplitudes for generalized one-dimensional nonlinear Schrodinger (NLS) equation of focusing type with saturated nonlinearity. All additional terms beyond the classical NLS equation are small. As initial conditions we use perturbed by weak noise modulationally unstable condensate. On the PDFs we observe power-law region for small and medium amplitudes followed by intermediate region and then Rayleigh far tail. Power-law region appears starting from some critical levels of average amplitude and coefficient related to saturated nonlinearity, and then becomes more pronounced with average amplitude and saturation coefficient. Correlation of phases becomes significant for large wave events and contributes about one order of magnitude to the frequencies of their occurrence. Waves statistics for the considered systems turns out to be exceptionally stable against additional stochastic forces.