title: Effect of the plasma density scale length on the direction of fast electrons in relativistic laser-solid interactions
abstract: The angular distribution of bremsstrahlung gamma rays produced by fast electrons accelerated in relativistic laser-solid interaction has been studied by photoneutron activation in copper. We show that the gamma-ray beam moves from the target normal to the direction of the k(laser) vector as the scale length is increased. Similar behavior is found also in 2D particle-in-cell simulations.
authors.affiliation: Plasma Physics Group, The Blackett Laboratory, Imperial College, London SW7 2BZ, United Kingdom.
authors.initials: MI
authors.lastname: Santala
authors.initials: M
authors.lastname: Zepf
authors.initials: I
authors.lastname: Watts
authors.initials: FN
authors.lastname: Beg
authors.initials: E
authors.lastname: Clark
authors.initials: M
authors.lastname: Tatarakis
authors.initials: K
authors.lastname: Krushelnick
authors.initials: AE
authors.lastname: Dangor
authors.initials: T
authors.lastname: McCanny
authors.initials: I
authors.lastname: Spencer
authors.initials: RP
authors.lastname: Singhal
authors.initials: KW
authors.lastname: Ledingham
authors.initials: SC
authors.lastname: Wilks
authors.initials: AC
authors.lastname: Machacek
authors.initials: JS
authors.lastname: Wark
authors.initials: R
authors.lastname: Allott
authors.initials: RJ
authors.lastname: Clarke
authors.initials: PA
authors.lastname: Norreys