Polarization effect of a Gaussian laser pulse on magnetic field influenced electron acceleration in vacuum

Abstract

Electron acceleration by a laser pulse in the presence of azimuthal magnetic field in vacuum has been analyzed. The azimuthal magnetic field influences the trajectory of an accelerated electron during the laser electron interaction in vacuum. The electron trajectory in the absence and presence of azimuthal magnetic field with a linearly polarized (LP) and circularly polarized (CP) laser pulses is analyzed. Due to the presence of azimuthal magnetic field, a confined trajectory of accelerated electron is observed in the direction of propagation of laser pulse. Resonance between the electron and the laser field occurs at optimum values of magnetic field, electron gains high energy from the laser and gets accelerated in the direction of propagation of laser pulse. The azimuthal magnetic field keeps the electron motion close to the axis parallel to the direction of propagation due to which the electron gains and retains high energy for longer distances. The electron energy gain is relatively higher with a CP laser pulse than that with LP laser pulse. The high energy gain of about 2 GeV is observed with a CP laser pulse of peak intensity 2.74×1020 W/cm2 in the presence of azimuthal magnetic field of 534 kG.