High-energy proton beam obtained by single high-power LG laser acceleration

Abstract

We used 3D particle-in-cell (PIC) simulations to investigate the eff ect of a single high-energy Laguerre-Gaussian laser pulse
interacting with an underdense plasma on the acceleration process of a proton beam. The single-beam LG laser drive solves the problem of
the need for external proton injection and the synchronization of two laser pulses. The circularly polarized LG laser fi rst takes protons out
of the high-density plasma target and pre-accelerates them through the radiation pressure acceleration mechanism (RPA). Then, when the
LG laser pulse enters the low-density plasma, a special cavity structure with electron columns will be formed due to the special transverse
intensity distribution of the LG laser. The self-injected proton in the special cavity will be accelerated while being confi ned to the center and
steadily accelerated by the tail fi eld of the cavity at very long distances.3D PIC simulation results show when using power density when
the LG laser is captured, the self-injected protons are accelerated to very high energies（the maximum energy of a proton is ）and lower
divergence.