title: Improvement of energy-conversion efficiency from laser to proton beam in a laser-foil interaction.
abstract: Improvement of energy-conversion efficiency from laser to proton beam is demonstrated by particle simulations in a laser-foil interaction. 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 multihole thin-foil target is proposed in order to increase the energy-conversion efficiency from laser to protons. The multiholes transpiercing the foil target help to enhance the laser-proton energy-conversion efficiency significantly. Particle-in-cell 2.5-dimensional ( x, y, vx, vy, vz) simulations present that the total laser-proton energy-conversion efficiency becomes 9.3% for the multihole target, though 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 as a new method to increase the energy-conversion efficiency from laser to ions.
authors.affiliation: Graduate School of Engineering, Utsunomiya University, 7-1-2 Yohtoh, Utsunomiya 321-8585, Japan. mt076627@cc.utsunomiya-u.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Nodera
authors.forename: S
authors.initials: S
authors.lastname: Kawata
authors.forename: N
authors.initials: N
authors.lastname: Onuma
authors.forename: J
authors.initials: J
authors.lastname: Limpouch
authors.forename: O
authors.initials: O
authors.lastname: Klimo
authors.forename: T
authors.initials: T
authors.lastname: Kikuchi