Exciting extreme events in the damped and AC-driven NLS equation through plane wave initial conditions

TL;DR

This study uses numerical simulations to explore how initial wave conditions influence rogue wave formation in a damped, forced nonlinear Schrödinger equation, revealing parameter effects and stability characteristics.

Contribution

It demonstrates the link between initial wave number and rogue wave emergence, and analyzes the influence of parameters and noise on these extreme events.

Findings

Wave number determines the number of rogue waves.

Norms of derivatives and powers detect rogue wave events.

Long-term behavior is governed by the system's attractor and stability.

Abstract

We investigate, by direct numerical simulations, the dynamics of the damped and forced nonlinear Schr\"odinger (NLS) equation in the presence of a time periodic forcing and for certain parametric regimes. It is thus revealed, that the wave-number of a plane-wave initial condition dictates the number of emerged Peregrine type rogue waves at the early stages of modulation instability. The formation of these events gives rise to the same number of transient "triangular" spatio-temporal patterns, each of which is reminiscent of the one emerging in the dynamics of the integrable NLS in its semiclassical limit, when supplemented with vanishing initial conditions. We find that the $L^2$-norm of the spatial derivative and the $L^4$-norm detect the appearance of rogue waves as local extrema in their evolution. The impact of the various parameters and noisy perturbations of the initial condition in affecting the above behavior is also discussed. The long time behaviour, in the parametric regimes where the extreme wave events are observable, is explained in terms of the global attractor possessed by the system and the asymptotic orbital stability of spatially uniform continuous wave solutions.