title: Observation of strong correlation between quasimonoenergetic electron beam generation by laser wakefield and laser guiding inside a preplasma cavity.
abstract: We use a one-shot measurement technique to study effects of laser prepulses on the electron laser wakefield acceleration driven by relativistically intense laser pulses (lambda=790 nm, 11 TW, 37 fs) in dense helium gas jets. A quasimonoenergetic electron bunch with an energy peak approximately 11.5 MeV[DeltaE/E approximately 10% (FWHM)] and with a narrow-cone angle (0.04pi mm mrad) of ejection is detected at a plasma density of 8 x 10(19) cm(-3). A strong correlation between the generation of monoenergetic electrons and optical guiding of the pulse in a thin channel produced by picosecond laser prepulses is observed. This generation mechanism is well corroborated by two-dimensional particle-in-cell simulations.
authors.affiliation: Nuclear Professional School, Graduate School of Engineering, University of Tokyo, 22-2 Shirane-shirakata, Tokai, Naka, Ibaraki 319-1188, Japan. hosokai@tokai.t.u-tokyo.ac.jp
authors.forename: Tomonao
authors.initials: T
authors.lastname: Hosokai
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kinoshita
authors.forename: Takeru
authors.initials: T
authors.lastname: Ohkubo
authors.forename: Akira
authors.initials: A
authors.lastname: Maekawa
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Uesaka
authors.forename: Alexei
authors.initials: A
authors.lastname: Zhidkov
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamazaki
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kotaki
authors.forename: Masaki
authors.initials: M
authors.lastname: Kando
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Nakajima
authors.forename: Sergei V
authors.initials: SV
authors.lastname: Bulanov
authors.forename: Paolo
authors.initials: P
authors.lastname: Tomassini
authors.forename: Antonio
authors.initials: A
authors.lastname: Giulietti
authors.forename: Danilo
authors.initials: D
authors.lastname: Giulietti