Modulated laser-induced acceleration of a relativistic charged particle

The acceleration of charged particles over short distances by a modulated laser pulse has promising applications in the development of advanced technology in fields such as material diagnostics and medicine. Herein, a mechanism is proposed to accelerate charged particles using multifrequency modulated circularly polarized laser pulses directed along the propagation direction of a constant uniform magnetic field. An exact analytical solution is obtained for the equation of motion of a relativistic charged particle in a modulated multifrequency electromagnetic field, and its phase-matching condition is observed. Upon investigation of several cases of initial conditions for the motion of a charged particle, oscillatory motion is revealed in the field of a modulated electromagnetic wave, which depends on the parameters of the modulated electromagnetic wave, as well as the translational motion of the particle. The condition for cyclotron auto-resonance in the field of an intense laser pulse is evaluated. Results indicate that the cyclotron auto-resonance is satisfied for nonrelativistic intensities of the laser field. Finally, the average kinetic energy in the field of a plane laser pulse and that in the field of a one-dimensional Gaussian beam are compared, showing that the former does not differ from the latter for any range of laser field intensities.