title: Surface oscillations in overdense plasmas irradiated by ultrashort laser pulses.
abstract: The generation of electron surface oscillations in overdense plasmas irradiated at normal incidence by an intense laser pulse is investigated. Two-dimensional (2D) particle-in-cell simulations show a transition from a planar, electrostatic oscillation at 2 omega, with omega the laser frequency, to a 2D electromagnetic oscillation at frequency omega and wave vector k > omega/c. A new electron parametric instability, involving the decay of a 1D electrostatic oscillation into two surface waves, is introduced to explain the basic features of the 2D oscillations. This effect leads to the rippling of the plasma surface within a few laser cycles, and is likely to have a strong impact on laser interaction with solid targets.
authors.affiliation: Dipartimento di Fisica and INFM, Sezione A, Universitá di Pisa, Pisa, Italy. macchi@df.unipi.it
authors.forename: A
authors.initials: A
authors.lastname: Macchi
authors.forename: F
authors.initials: F
authors.lastname: Cornolti
authors.forename: F
authors.initials: F
authors.lastname: Pegoraro
authors.forename: T V
authors.initials: TV
authors.lastname: Liseikina
authors.forename: H
authors.initials: H
authors.lastname: Ruhl
authors.forename: V A
authors.initials: VA
authors.lastname: Vshivkov