title: Transverse interferometry of a hydrogen-filled capillary discharge waveguide.
abstract: Transverse interferometric measurements are presented of the plasma channel formed in a hydrogen-filled capillary discharge waveguide recently used to generate 1 GeV electrons in a laser-driven plasma accelerator for the first time. The measurements were found to be in good agreement with nonlocal thermal equilibrium simulations, but showed significant differences with the results of a quasistatic model developed by Bobrova et al. [Phys. Rev. E. 65, 016407 (2001)]. The measurements are used to determine scaling laws for the axial electron density and matched spot size of the plasma channel, enabling optimization of the channel to specific applications.
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Oxford OX1 3PU, United Kingdom.
authors.forename: A J
authors.initials: AJ
authors.lastname: Gonsalves
authors.forename: T P
authors.initials: TP
authors.lastname: Rowlands-Rees
authors.forename: B H P
authors.initials: BH
authors.lastname: Broks
authors.forename: J J A M
authors.initials: JJ
authors.lastname: van der Mullen
authors.forename: S M
authors.initials: SM
authors.lastname: Hooker