Influence of nitrogen concentration on laser wakefield acceleration of electrons driven by Bessel-Gauss laser beam

Abstract

This paper investigates laser wakefield acceleration (LWFA) of electrons using two-stage gas nozzles and ionization injection schemes. We present Fourier–Bessel particle-in-cell (FBPIC) simulation results for LWFA of electrons driven by Bessel-Gauss (BG) laser beams in hydrogen and hydrogen-nitrogen gas mixtures with varying nitrogen concentrations. A TW-class ultrashort 10 fs laser beam is employed to study the effect of different nitrogen gas concentrations on the electron beam quality up to an acceleration distance of 1 mm. Results indicate that electron energy is the lowest in pure hydrogen, while adding nitrogen enhances energy levels. Moreover, it is found that the highest electron energy is obtained when the nitrogen concentration is 1%, and the electron energy reaches around 150 MeV. Higher nitrogen concentrations (> 1%) also lead to reduced electron energy, demonstrating a declining trend with further increases.