From thermonuclear fusion to Hamiltonian chaos

This paper aims at a historical and pedagogical presentation of some important contributions of the research on thermonuclear fusion by magnetic confinement to the study of Hamiltonian chaos. This chaos is defined with the help of Poincaré maps on a simple two-wave Hamiltonian system. A simple criterion for computing the transition to large scale chaos is introduced. A renormalization group approach for barriers in phase space is described pictorially. The geometrical structure underlying chaos is introduced, and then described in the adiabatic limit of Hamiltonian chaos. The issue of chaotic transport is discussed in simple limit cases.