Perturbation-induced decay of an envelope soliton

Interaction of a hf wave field envelope soliton with a If (acoustic) wave, described by the Zakharov system, results in a radiative decay of the soliton into quasi-linear hf envelope waves (plasmons). The plasmon number emission rate, its spectral composition, and the soliton’s decay rate are calculated, for the subsonic case, by means of perturbation theory based on the inverse scattering transform. The calculation is performed for three cases: A monochromatic acoustic wave, a non-monochromatic wave packet, and a random acoustic wave field. Emission from a damped nonlinear SchrɆdinger (NS) soliton driven by an external ac field, and radiative decay of a NS soliton under the action of nonlinear Landau damping are investigated too. At last, some results concerning the stability of a NS two-soliton breather subject to the action of Hamiltonian perturbations are obtained.