Enhancement of electron injection in laser wakefield acceleration using auxiliary interfering pulses

A relatively simple interfering-pulses-assisted laser wakefield acceleration (IPA-LWFA) scheme is proposed for enhancing the charge of the LWFA electron bunch. Prior to the short intense pump pulse, two long low-intensity auxiliary laser pulses first interact in the plasma and excite a slow electron plasma wave at the beat frequency. The weak but finite-amplitude plasma wave energizes the affected electrons and acts like a slow-moving grating. Particle-in-cell simulations show that electron trapping in the wakefield of the pump laser pulse, which arrives at a later time, can be significantly enhanced. The charge of the IPA-LWFA electron bunch depends mainly on the intensity of the auxiliary pulses and the time delay of the pump laser.