title: Detailed Experimental Study of Ion Acceleration by Interaction of an Ultra-Short Intense Laser with an Underdense Plasma.
abstract: Ion acceleration from intense (Iλ(2) > 10(18) Wcm(-2) μm(2)) laser-plasma interaction is experimentally studied within a wide range of He gas densities. Focusing an ultrashort pulse (duration  ion plasma period) on a newly designed submillimetric gas jet system, enabled us to inhibit total evacuation of electrons from the central propagation channel reducing the radial ion acceleration associated with ponderomotive Coulomb explosion, a mechanism predominant in the long pulse scenario. New ion acceleration mechanism have been unveiled in this regime leading to non-Maxwellian quasi monoenergetic features in the ion energy spectra. The emitted nonthermal ion bunches show a new scaling of the ion peak energy with plasma density. The scaling identified in this new regime differs from previously reported studies.
authors.affiliation: Laboratoire d'Optique Appliquée, Ecole Polytechnique, ENSTA, CNRS, UMR 7639, 91761 Palaiseau, France.|ELI-ALPS, ELI-Hu Nkft, Dugonics ter 13, Szeged 6720, Hungary.
authors.forename: S
authors.initials: S
authors.lastname: Kahaly
authors.affiliation: Laboratoire d'Optique Appliquée, Ecole Polytechnique, ENSTA, CNRS, UMR 7639, 91761 Palaiseau, France.|SourceLAB SAS, 86 rue de Paris, F-91400 Orsay, France.
authors.forename: F
authors.initials: F
authors.lastname: Sylla
authors.affiliation: Laboratoire d'Optique Appliquée, Ecole Polytechnique, ENSTA, CNRS, UMR 7639, 91761 Palaiseau, France.
authors.forename: A
authors.initials: A
authors.lastname: Lifschitz
authors.affiliation: Laboratoire d'Optique Appliquée, Ecole Polytechnique, ENSTA, CNRS, UMR 7639, 91761 Palaiseau, France.
authors.forename: A
authors.initials: A
authors.lastname: Flacco
authors.affiliation: Laboratoire d'Optique Appliquée, Ecole Polytechnique, ENSTA, CNRS, UMR 7639, 91761 Palaiseau, France.
authors.forename: M
authors.initials: M
authors.lastname: Veltcheva
authors.affiliation: Laboratoire d'Optique Appliquée, Ecole Polytechnique, ENSTA, CNRS, UMR 7639, 91761 Palaiseau, France.
authors.forename: V
authors.initials: V
authors.lastname: Malka