Dynamics of a charged particle in progressive plane waves propagating in vacuum or plasma: Stochastic acceleration

Abstract

AbstractThe dynamics of a charged particle in a relativistic strong electromagnetic plane wave propagating in a nonmagnetized medium is studied first. The problem is shown to be integrable when the wave propagates in vacuum. When it propagates in plasma, and when the full plasma response is considered, an exhaustive numerical work allows us to conclude that the problem is not integrable. The dynamics of a charged particle in a relativistic strong electromagnetic plane wave propagating along a constant homogeneous magnetic field is studied next. The problem is integrable when the wave propagates in vacuum. When it propagates in plasma, the problem becomes nonintegrable. Finally, one particle in a high intensity wave, propagating in a nonmagnetized medium, perturbed by a low intensity traveling wave is considered. Resonances are identified and conditions for resonance overlap are studied. Stochastic acceleration is shown by considering a single particle. It is confirmed in plasma in realistic situations with particle-in-cell code simulations.