  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.
