title: Observation of a long-wavelength hosing modulation of a high-intensity laser pulse in underdense plasma.
abstract: We report the first experimental observation of a long-wavelength hosing modulation of a high-intensity laser pulse. Side-view images of the scattered optical radiation at the fundamental wavelength of the laser reveal a transverse oscillation of the laser pulse during its propagation through underdense plasma. The wavelength of the oscillation λ(hosing) depends on the background plasma density n(e) and scales as λ(hosing)∼n(e)(-3/2). Comparisons with an analytical model and two-dimensional particle-in-cell simulations reveal that this laser hosing can be induced by a spatiotemporal asymmetry of the intensity distribution in the laser focus which can be caused by a misalignment of the parabolic focusing mirror or of the diffraction gratings in the pulse compressor.
authors.affiliation: The Blackett Laboratory, Imperial College London, London SW7 2BZ, United Kingdom.
authors.forename: M C
authors.initials: MC
authors.lastname: Kaluza
authors.forename: S P D
authors.initials: SP
authors.lastname: Mangles
authors.forename: A G R
authors.initials: AG
authors.lastname: Thomas
authors.forename: Z
authors.initials: Z
authors.lastname: Najmudin
authors.forename: A E
authors.initials: AE
authors.lastname: Dangor
authors.forename: C D
authors.initials: CD
authors.lastname: Murphy
authors.forename: J L
authors.initials: JL
authors.lastname: Collier
authors.forename: E J
authors.initials: EJ
authors.lastname: Divall
authors.forename: P S
authors.initials: PS
authors.lastname: Foster
authors.forename: C J
authors.initials: CJ
authors.lastname: Hooker
authors.forename: A J
authors.initials: AJ
authors.lastname: Langley
authors.forename: J
authors.initials: J
authors.lastname: Smith
authors.forename: K
authors.initials: K
authors.lastname: Krushelnick