Particle acceleration by subcycle laser pulse in vacuum

An analytical model based on the diffraction-induced transformation [ A. E. Kaplan , J. Opt. Soc. Am. B 15 , 951 ( 1998 ) ] for an ultrashort subcycle laser pulse propagating in vacuum is considered. The pulse is initially Gaussian. To the lowest order of the diffraction angle its evolution satisfies Maxwell's equations. The model is used to study the motion of charged particles in the pulse. It is shown that the delta-function representation is an excellent approximation of a subcycle pulse for studying charged-particle dynamics in subcycle pulse.