Quantitative analysis of the wave polarization effect on electron capture in a laser acceleration channel

Abstract

The main purpose of this paper is to explore thoroughly the polarization effect in the capture and acceleration scenario (CAS) scheme using Jones vectors, as well as to conduct a quantitative study of the characteristics of electron beams interacting with EM fields with any polarization states. The simulation provides a circulating hollow electron beam suitable for high-energy particle physics experiments. In this paper, by properly injecting low-energy free electrons into the acceleration channel of a laser pulse in optimal polarization state with an intensity of a0≡eE0/m0cω0=15, a satisfactory result was achieved compared to other works that used extra-high intensity laser pulses (a0≃100). It was observed that the characteristics of the output beam for circular polarization, compared to other polarizations, have more advantages, such as showing less energy spread and spatial divergence, although the mean energy in this case is lower than in other polarizations. Moreover, for a circularly polarized (CP) field, the total fraction of CAS electrons can reach over 98% of the incident electrons. These features demonstrate that the circular polarization in the CAS scheme provides greater acceleration efficiency.