title: Dense attosecond electron sheets from laser wakefields using an up-ramp density transition.
abstract: Controlled electron injection into a laser-driven wakefield at a well defined space and time is reported based on particle-in-cell simulations. Key novel ingredients are an underdense plasma target with an up-ramp density profile followed by a plateau and a fairly large laser focus diameter that leads to an essentially one-dimensional (1D) regime of laser wakefield, which is different from the bubble (complete blowout) regime occurring for tightly focused drive beams. The up-ramp profile causes 1D wave breaking to occur sharply at the up-ramp-plateau transition. As a result, it generates an ultrathin (few nanometer, corresponding to attosecond duration), strongly overdense relativistic electron sheet that is injected and accelerated in the wakefield. A peaked electron energy spectrum and high charge (∼nC) distinguish the final sheet.
authors.affiliation: Key Laboratory for Laser Plasmas (MoE) and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: F Y
authors.initials: FY
authors.lastname: Li
authors.forename: Z M
authors.initials: ZM
authors.lastname: Sheng
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: J
authors.initials: J
authors.lastname: Meyer-ter-Vehn
authors.forename: W B
authors.initials: WB
authors.lastname: Mori
authors.forename: W
authors.initials: W
authors.lastname: Lu
authors.forename: J
authors.initials: J
authors.lastname: Zhang