Efficient Production of Proton Beam in Laser-Illuminated Tailored Microstructured Target

In a proton beam generation by a laser-foil interaction, significant improvement of energy-conversion efficiency from laser to proton beam is presented by particle simulations. When an intense short-pulse laser illuminates the thin-foil target, the foil electrons are accelerated around the target by the ponderomotive force. The hot electrons generate a strong electric field, which accelerates the foil protons, and the proton beam is generated. In this paper, a tailored multihole thin-foil target is proposed in order to increase the energy-conversion efficiency from laser to protons. The multiholes transpiercing the foil target enhance the laser-proton energy-conversion efficiency significantly. Particle-in-cell 2.5-dimensional simulations present that the total laser-proton energy-conversion efficiency becomes 9.3% for the tailored multihole target, although the energy-conversion efficiency is 1.5% for a plain thin-foil target. The maximum proton energy is 10.0 MeV for the multihole target and is 3.14 MeV for the plain target. The transpiercing multihole target serves a new method to increase the energy-conversion efficiency from laser to ions.