title: Electron-yield enhancement in a laser-wakefield accelerator driven by asymmetric laser pulses.
abstract: The effect of asymmetric laser pulses on electron yield from a laser wakefield accelerator has been experimentally studied using >10(19) cm(-3) plasmas and a 10 TW, >45 fs, Ti:Al2O3 laser. The laser pulse shape was controlled through nonlinear chirp with a grating pair compressor. Pulses (76 fs FWHM) with a steep rise and positive chirp were found to significantly enhance the electron yield compared to pulses with a gentle rise and negative chirp. Theory and simulation show that fast rising pulses can generate larger amplitude wakes that seed the growth of the self-modulation instability, and that frequency chirp is of minimal importance for the experimental parameters.
authors.affiliation: Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA.
authors.forename: W P
authors.initials: WP
authors.lastname: Leemans
authors.forename: P
authors.initials: P
authors.lastname: Catravas
authors.forename: E
authors.initials: E
authors.lastname: Esarey
authors.forename: C G R
authors.initials: CG
authors.lastname: Geddes
authors.forename: C
authors.initials: C
authors.lastname: Toth
authors.forename: R
authors.initials: R
authors.lastname: Trines
authors.forename: C B
authors.initials: CB
authors.lastname: Schroeder
authors.forename: B A
authors.initials: BA
authors.lastname: Shadwick
authors.forename: J
authors.initials: J
authors.lastname: Van Tilborg
authors.forename: J
authors.initials: J
authors.lastname: Faure