Asymptotic integrability and Hamilton theory of soliton motion along large-scale background waves

We consider the problem of soliton mean-field interaction for the class of asymptotically integrable equations, where the notion of asymptotic integrability means that the Hamilton equations for a high-frequency wave packet's propagation along a large-scale background wave have an integral of motion. Using Stokes' remark, we transform this integral to an integral for the soliton equations of motion and then derive the Hamilton equations for the soliton dynamics in a universal form expressed in terms of the Riemann invariants for the hydrodynamic background wave. The physical properties are specified by the concrete expressions for the Riemann invariants. The theory is illustrated by its application to soliton dynamics, which is described by the Kaup-Boussinesq system.