Inertial Fusion Sciences and Applications 2005
J.-C. Gauthier, et al.
J. Phys. IV France 133 (2006) 1151-1153
DOI: 10.1051/jp4:2006133235

Ion acceleration using high-contrast ultra-intense lasers

J. Fuchs¹, P. Antici^{1, 2}, E. d'Humières³, E. Lefebvre³, M. Borghesi⁴, E. Brambrink¹, C. Cecchetti⁴, T. Toncian⁵, H. Pépin⁶ and P. Audebert<sup>1

1</sup>  Laboratoire pour l'Utilisation des Lasers Intenses, UMR 7605 CNRS-CEA, École Polytechnique-Université Paris VI, 91128 Palaiseau, France
²  Dipartimento di Energetica, Università di Roma "La Sapienza", Via Scarpa 14-16, 00165 Roma, Italy
³  DPTA, CEA-DIF, 91680 Bruyères-le-Châtel, France
⁴  School of Mathematics and Physics, The Queen's University, Belfast, UK
⁵  Institut für Laser und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf, Germany
⁶  INRS-ÉMT, 1650 Bd. L. Boulet, J3X1S2 Varennes, Québec, Canada

Abstract
We have compared the acceleration of high-energy ions from the rear-surface of thin foils for various contrast conditions of the ultra-intense laser pulse irradiating the targets. The experiments were performed using the LULI 100 TW facility. We used Al targets of variable thicknesses and the laser pulse contrast ratio ahead of the main pulse was varied using either a fast Pockels cell or a single or double plasma mirror. The latter was installed at an intermediate field position, in between the focusing optics and the target, so that its effect was optimized. By improving with these two methods the laser pulse contrast, we have observed that we could significantly reduce the thickness of the target used for proton acceleration and at the same time increase both the cut-off energy of the accelerated protons and the energy conversion efficiency of the process.

© EDP Sciences 2006