Boosting of proton beam quality by a pair of low-intensity reverse laser pulses

An attempt has been made to boost the proton beam quality using the multiple counter-propagating laser pulses target interaction with the help of particle-in-cell simulation. Here, we show that a pair of low-intensity reversely incident laser pulses can significantly improve the proton beam quality, i.e., leading to generating a highly peaked monoenergetic proton beam with reduced energy spread. The reverse laser pulses not only help to guide the main laser but also provide initial momentum to the target electrons and thus protons, which is very crucial for efficient acceleration. As a result, a high-quality (sharp narrow peak) monoenergetic proton beam, with energy spectra peaked around GeV, can be obtained for the pulse energies at the level of 50 J. Furthermore, the effects of the time delay for the main laser pulse and the distances between the incident points of the reverse laser pulses are also investigated.