title: High-contrast laser acceleration of relativistic electrons in solid cone-wire targets.
abstract: The consequences of small scale-length precursor plasmas on high-intensity laser-driven relativistic electrons are studied via experiments and simulations. Longer scale-length plasmas are shown to dramatically increase the efficiency of electron acceleration, yet, if too long, they reduce the coupling of these electrons into the solid target. Evidence for the existence of an optimal plasma scale-length is presented and estimated to be from 1 to 5μm. Experiments on the Trident laser (I=5×10(19)W/cm(2)) diagnosed via Kα emission from Cu wires attached to Au cones are quantitively reproduced using 2D particle-in-cell simulations that capture the full temporal and spatial scale of the nonlinear laser interaction and electron transport. The simulations indicate that 32%±8%(6.5%±2%) of the laser energy is coupled into electrons of all energies (1-3 MeV) reaching the inner cone tip and that, with an optimized scale-length, this could increase to 35% (9%).
authors.affiliation: University of California-San Diego, La Jolla, California 92093, USA.|Lawrence Livermore National Laboratory, Livermore, California 94440, USA.
authors.forename: D P
authors.initials: DP
authors.lastname: Higginson
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94440, USA.
authors.forename: A
authors.initials: A
authors.lastname: Link
authors.affiliation: University of California-San Diego, La Jolla, California 92093, USA.|Department of Physics, University of Nevada, Reno, Nevada 89557, USA.
authors.forename: H
authors.initials: H
authors.lastname: Sawada
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94440, USA.
authors.forename: S C
authors.initials: SC
authors.lastname: Wilks
authors.affiliation: University of California-San Diego, La Jolla, California 92093, USA.|Lawrence Livermore National Laboratory, Livermore, California 94440, USA.
authors.forename: T
authors.initials: T
authors.lastname: Bartal
authors.affiliation: University of California-San Diego, La Jolla, California 92093, USA.|Lawrence Livermore National Laboratory, Livermore, California 94440, USA.
authors.forename: S
authors.initials: S
authors.lastname: Chawla
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94440, USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Chen
authors.affiliation: Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Flippo
authors.affiliation: University of California-San Diego, La Jolla, California 92093, USA.|Lawrence Livermore National Laboratory, Livermore, California 94440, USA.
authors.forename: L C
authors.initials: LC
authors.lastname: Jarrott
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94440, USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Key
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94440, USA.
authors.forename: H S
authors.initials: HS
authors.lastname: McLean
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94440, USA.
authors.forename: P K
authors.initials: PK
authors.lastname: Patel
authors.affiliation: Lawrence Livermore National Laboratory, Livermore, California 94440, USA.|Laboratoire pour l'Utilisation des Lasers Intenses, UMR 7605 CNRS-CEA-École Polytechnique-Université Paris VI, 91128 Palaiseau, France.
authors.forename: F
authors.initials: F
authors.lastname: Pérez
authors.affiliation: University of California-San Diego, La Jolla, California 92093, USA.|General Atomics, San Diego, California 92186, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Wei
authors.affiliation: University of California-San Diego, La Jolla, California 92093, USA.
authors.forename: F N
authors.initials: FN
authors.lastname: Beg