DIFFUSION IN HAMILTONIAN-SYSTEMS

The study is reported of a diffusion in a model of degenerate Hamilton ian systems. The Hamiltonian under consideration is the sum of a linea r function of action variables and a periodic function of angle variab les. Under certain choices of these functions the diffusion of action variables exists. In the case of two degrees of freedom during the pro cess of diffusion, the vector of the action variables returns many tim es near its initial value. In the case of three degrees of freedom the choice of Hamiltonian allows one to obtain a diffusion rate faster th an any prescribed one. (C) 1998 American Institute of Physics.