Simulation of positron acceleration in the wakefield of sine laser pulses

In order to study the kinetic energy of the accelerated positron in the laser-driven wakefield induced from the interaction of sine laser pulse and the low density plasma,the kinetic energy of positron in the wakefield driven by the symmetric and asymmetric sine laser pulses was numerically simulated.Numerical results show that the number of the accelerated positrons in the wakefield and their initial speed are increased due to the effect of Raman scattering.Moreover,since the rising part of the asymmetric sine pulse is steeper than the symmetric sine pulse,the positrons obtain a higher pondermotive potential and the asymmetric sine pulse induces a high intensity wakefield.As a result,the kinetic energy of the positrons driven by the asymmetric sine laser pulse is higher than that driven by the symmetric sine laser pulse.These results indicate that the asymmetric sine laser pulse can effectively improve the acceleration efficiency of the positrons.