title: Laser-Accelerated Ions from a Shock-Compressed Gas Foil.
abstract: We present results of energetic laser-ion acceleration from a tailored, near solid density gas target. Colliding hydrodynamic shocks compress a pure hydrogen gas jet into a 70  μm thick target prior to the arrival of the ultraintense laser pulse. A density scan reveals the transition from a regime characterized by a wide angle, low-energy beam (target normal sheath acceleration) to one of a more focused beam with a high-energy halo (magnetic vortex acceleration). In the latter case, three-dimensional simulations show the formation of a Z pinch driven by the axial current resulting from laser wakefield accelerated electrons. Ions at the rear of the target are then accelerated by a combination of space charge fields from accelerated electrons and Coulombic repulsion as the pinch dissipates.
authors: Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375, USA.
authors: M H
authors: MH
authors: Helle
authors: Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375, USA.
authors: D F
authors: DF
authors: Gordon
authors: Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375, USA.
authors: D
authors: D
authors: Kaganovich
authors: Research Support Instruments, Lanham, Maryland 20706, USA.
authors: Y
authors: Y
authors: Chen
authors: Plasma Physics Division, Naval Research Laboratory, Washington, D.C. 20375, USA.
authors: J P
authors: JP
authors: Palastro
authors: Research Support Instruments, Lanham, Maryland 20706, USA.
authors: A
authors: A
authors: Ting