title: Role of Direct Laser Acceleration of Electrons in a Laser Wakefield Accelerator with Ionization Injection.
abstract: We show the first experimental demonstration that electrons being accelerated in a laser wakefield accelerator operating in the forced or blowout regimes gain significant energy from both the direct laser acceleration (DLA) and the laser wakefield acceleration mechanisms. Supporting full-scale 3D particle-in-cell simulations elucidate the role of the DLA of electrons in a laser wakefield accelerator when ionization injection of electrons is employed. An explanation is given for how electrons can maintain the DLA resonance condition in a laser wakefield accelerator despite the evolving properties of both the drive laser and the electrons. The produced electron beams exhibit characteristic features that are indicative of DLA as an additional acceleration mechanism.
authors.affiliation: University of California Los Angeles Department of Electrical Engineering, Los Angeles, California 90095, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Shaw
authors.affiliation: University of California Los Angeles Department of Electrical Engineering, Los Angeles, California 90095, USA.
authors.forename: N
authors.initials: N
authors.lastname: Lemos
authors.affiliation: University of California Los Angeles Department of Physics and Astronomy, Los Angeles, California 90095, USA.|GoLP/Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal.
authors.forename: L D
authors.initials: LD
authors.lastname: Amorim
authors.affiliation: University of California Los Angeles Department of Electrical Engineering, Los Angeles, California 90095, USA.
authors.forename: N
authors.initials: N
authors.lastname: Vafaei-Najafabadi
authors.affiliation: University of California Los Angeles Department of Electrical Engineering, Los Angeles, California 90095, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Marsh
authors.affiliation: University of California Los Angeles Department of Physics and Astronomy, Los Angeles, California 90095, USA.
authors.forename: F S
authors.initials: FS
authors.lastname: Tsung
authors.affiliation: University of California Los Angeles Department of Electrical Engineering, Los Angeles, California 90095, USA.|University of California Los Angeles Department of Physics and Astronomy, Los Angeles, California 90095, USA.
authors.forename: W B
authors.initials: WB
authors.lastname: Mori
authors.affiliation: University of California Los Angeles Department of Electrical Engineering, Los Angeles, California 90095, USA.
authors.forename: C
authors.initials: C
authors.lastname: Joshi