INTERNAL-FRICTION BETWEEN SOLITONS IN NEAR-INTEGRABLE SYSTEMS

We study inelastic interactions (internal friction) between two solito ns in a system described by a near-integrable generalized nonlinear Sc hrodinger equation. An analytic method for calculating the radiation i ntensity and the rates of amplitude changes of two interacting soliton s is proposed. This method shows that, in the limit of zero angle of c ollision, the amplitude of the smaller soliton decays so that it is in versely proportional to the cube root of the propagation distance. The radiation losses associated with the internal friction of two soliton s occur at the expense of the smaller soliton. Half of the energy lost from the smaller soliton is radiated and half goes to the larger soli ton. The results obtained by use of our analytic method are in excelle nt agreement with numerical simulations.