Anisotropy of Electrons Accelerated by a High-Intensity Laser Pulse

We describe a realistic model for a focused high-intensity laser pulse in three dimensions. Relativistic dynamics of an electron submitted to such pulse is described by equations of motion with ponderomotive potential depending on a single free parameter in the problem, which we refer to as the "asymmetry parameter". It is shown that the asymmetry parameter can be chosen to provide quantitative agreement of the developed theory with experimental results of Malka et al. [Phys. Rev. Lett. 78, 3314 (1997)] who detected angular asymmetry in the spatial pattern of electrons accelerated in vacuum by a high-intensity laser pulse.