STABILITY OF BREATHERS AND DESTRUCTIVE SOLITON SOLITON COLLISIONS IN A PERTURBED NONLINEAR SCHRODINGER-EQUATION

We consider soliton-soliton interactions in the damped ac-driven nonli near Schrodinger equation, which is the simplest model of charge-densi ty wave conductor or of a cold plasma driven by an external ac electri c field. Analyzing perturbatively the collision of two solitons with z ero initial velocity at infinity, we demonstrate that after the collis ion the solitons separate at a finite velocity, i.e., a two-soliton br eather does not exist in this model. We corroborate this analytical pr ediction by direct numerical simulations. We also demonstrate that sol iton-soliton collisions in the model considered are practically always destructive: after collision, the solitons find themselves kicked out from the stable states, phase-locked to the ac drive, and finally the y fully decay under the action of dissipation. Using the results obtai ned, we calculate a contribution of the solitons to the rate of absorp tion of energy of the ac field, which is the most important experiment ally observable characteristic of the above-mentioned ac-driven system s.