SCATTERING OF ENVELOPE SOLITONS BY A MASS IMPURITY IN NONLINEAR LATTICES

Scatterings of nonlinear lattice waves by a mass impurity are studied. The waves are assumed to be nonlinear modulations of the monochromatic waves. Due to the impurity there appear the incident, reflected and transmitted waves. We show that the three waves are described by independent Nonlinear Schrodinger (NLS) equations respectively. Using the continuity conditions of the waves at the impurity site, we analytically construct the transmitted and reflected waves from the incident wave. As an application, scattering of an incident NLS envelope soliton is investigated. We find that at most one soliton is generated both in the reflected wave and in the transmitted wave.