title: Hot-electron distribution functions in a subpicosecond laser interaction with solid targets of varying initial gradient scale lengths.
abstract: We have studied the distribution function of the hot electrons produced during the interaction of a 120-fs, 60-mJ, 800-nm wavelength and a p-polarized laser pulse with bilayered Al/Fe targets. The main pulse interacts with a preformed plasma, obtained with a controlled prepulse, whose density gradient scale length has been measured. The electron distribution function is characterized by means of the Kalpha emission of the two materials of the target as a function of the Al-layer thickness. The low-energy region (<50 keV) of the hot-electron distribution function shows no dependency in shape on the gradient scale length, but only a variation in the total number of the generated electrons. The comparison between the experimental results and the particle-in-cell and Monte Carlo calculations of the electron distribution function and the Kalpha emission is gratifying.
authors.affiliation: Laboratoire pour l'Utilisation des Lasers Intenses, UMR No. 7605 CNRS, Ecole Polytechnique, CEA, Université Paris VI, Ecole Polytechnique, 91128 Palaiseau, France.
authors.forename: S
authors.initials: S
authors.lastname: Bastiani
authors.forename: P
authors.initials: P
authors.lastname: Audebert
authors.forename: J P
authors.initials: JP
authors.lastname: Geindre
authors.forename: T
authors.initials: T
authors.lastname: Schlegel
authors.forename: J C
authors.initials: JC
authors.lastname: Gauthier
authors.forename: C
authors.initials: C
authors.lastname: Quoix
authors.forename: G
authors.initials: G
authors.lastname: Hamoniaux
authors.forename: G
authors.initials: G
authors.lastname: Grillon
authors.forename: A
authors.initials: A
authors.lastname: Antonetti