Covariant formulation of wave-particle interaction in a transverse magnetic field

We consider the interaction of relativistic charged particles with a perpendicular monochromatic wave of arbitrary amplitude in the presence of a static magnetic field. We introduce a covariant formulation based on a super-Hamiltonian and we study the energy-time phase plane. This formalism considerably simplifies the analysis of the problem and improves previous theoretical models. It is shown that the system dynamics for the monochromatic perturbation is quite different from the usual wave-packet perturbation: with the present formulation a finite stochastic web with three topologically distinct regions is observed.