Reduction of Electron Dephasing Rate by Bessel Function Laser Pulse Propagation in Underdense Plasma (April 2021)

In laser acceleration dynamics of the electron, the approximate value of the longitudinal component of the electric field has been considered in all analytical and numerical calculations. In this article, an exact analytical expression for the longitudinal component of the electric field in a spindle-shaped laser-produced plasma channel formed by Bessel laser pulse propagation is derived. To this end, first, the dimensions of the channel are obtained by balancing the ponderomotive and electrostatic forces acting on the plasma channel, and then an analytical expression for the longitudinal electric field of the channel is calculated. Finally, substituting the exact fields in the electron equation of motion, the dynamics of the electron inside the channel and also the electron energy gain are studied. The result of the numerical analysis shows that the real longitudinal component of the electric field of the channel changes the electron energy gain significantly. We also found that the longitudinal electric field of laser does not always counteract the transverse component of the field so that the electron can gain or lose energy from both of them simultaneously.