title: Proton acceleration with high-intensity ultrahigh-contrast laser pulses.
abstract: We report on simultaneous measurements of backward- and forward-accelerated protons spectra when an ultrahigh intensity (approximately 5 x 10(18) W/cm(20), ultrahigh contrast (>10(10)) laser pulse interacts with foils of thickness ranging from 0.08 to 105 microm. Under such conditions, free of preplasma originating from ionization of the laser-irradiated surface, we show that the maximum proton energies are proportional to the p component of the laser electric field only and not to the ponderomotive force and that the characteristics of the proton beams originating from both target sides are almost identical. All these points have been corroborated by extensive 1D and 2D particle-in-cell simulations showing a very good agreement with the experimental data.
authors.affiliation: Service des Photons, Atomes et Molécules, Commissariat à l'Energie Atomique, DSM/DRECAM, CEN Saclay, 91191 Gif sur Yvette, France.
authors.forename: T
authors.initials: T
authors.lastname: Ceccotti
authors.forename: A
authors.initials: A
authors.lastname: Lévy
authors.forename: H
authors.initials: H
authors.lastname: Popescu
authors.forename: F
authors.initials: F
authors.lastname: Réau
authors.forename: P
authors.initials: P
authors.lastname: D'Oliveira
authors.forename: P
authors.initials: P
authors.lastname: Monot
authors.forename: J P
authors.initials: JP
authors.lastname: Geindre
authors.forename: E
authors.initials: E
authors.lastname: Lefebvre
authors.forename: Ph
authors.initials: P
authors.lastname: Martin