Effects of underdense preplasma on the energetic proton generation in ultraintense short laser pulse interaction with an overdense plasma slab

Abstract

High-energy proton generation from the interaction of an ultraintense femtosecond laser pulse with an overdense plasma slab combined with an underdense preplasma has been studied by using two-dimensional, fully electromagnetic and relativistic particle-in-cell simulations. With a proper condition of the preplasma, it was observed that the forwardly directed proton acceleration from the rear side of the plasma slab was surely enhanced and the resulting proton beams had a better directionality compared to those in case of no preplasma. For the detailed analysis, the proton momentum distribution, and the angular distribution of the accelerated protons were investigated with the variation of target thickness, laser intensity, and preplasma scale length.