Electron acceleration in combined laser and uniform electric fields

An exact analytical solution for the equation of motion of a single relativ istic electron, injected initially at some angle xi to the propagation dire ction of a linearly polarized plane-wave laser field of arbitrary intensity and a uniform electric field oriented anti-parallel to the laser propagati on direction, is developed. The solution is then used to investigate the is sue of electron acceleration to high energies in the prescribed fields. It is found that, in principle, an electron may be accelerated from rest or mo tion to several hundred GeV, if the uniform electric field strength E-s app roaches a critical value E-s(c) = (m<(<omega>)over tilde>c)/(2 pi Ne), wher e m and e are the mass and charge of the electron, c is the speed of light in vacuum, N is the number of field cycles in the pulse and <(<omega>)over tilde> is the Doppler-shifted frequency of the laser field as seen by the e lectron upon initial injection. The radiation losses during acceleration ar e shown to be negligible and the spectrum of the radiation emitted along th e initial direction of motion (parallel injection) of the electron is shown to consist mostly of the fundamental laser frequency.