Target-normal sheath acceleration (TNSA) of protons from a solid-density plasma target consisting of a thin foil, with a thin hydrogen layer behind it and a plasma-filled tube with a parabolic density profile at its front, is investigated using two-dimensional particle-in-cell simulation. It is found that the targetback sheath field induced by the laser driven hot electrons is double peaked, so that the protons are additionally accelerated. The hot sheath electrons, and thus the TNSA protons, depend strongly on the tube plasma, which unlike the preplasma caused by the laser prepulse can be easily controlled. It is also found that the most energetic and best collimated TNSA protons are produced when the tube plasma is of near-critical density. Published by AIP Publishing.

ION-ACCELERATION; BEAMS; RADIATION; DRIVEN; PULSES; ENERGY

Peking University; SHENZHEN TECHNOLOGY UNIVERSITY; China Academy Of Engineering Physics