The impact of contaminants on laser-driven light ion acceleration

Journal Article · Fri Oct 15 00:00:00 EDT 2010 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3497002· OSTI ID:21421289

Petrov, G M; Davis, J; Petrova, Tz ^[1]; Willingale, L; Maksimchuk, A; Krushelnick, K ^[2]

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1. Plasma Physics Division, Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, DC 20375 (United States)
2. Center for Ultrafast Optical Science, University of Michigan, 2200 Bonisteel Blvd., Ann Arbor, Michigan 48109 (United States)

The impact of contaminants on laser-driven ion acceleration is investigated using particle-in-cell simulations. The conventional ion acceleration mechanism, target normal sheath acceleration, has been revisited for targets with proton-rich contaminants in the form of water vapor. The targets considered have a deuterated plastic layer on the rear surface of an aluminum target, and the influence of the contaminant layer on the deuteron acceleration is investigated. In the early stage of ion acceleration, the space-charge electrostatic field on the rear target surface accelerates only the outermost, proton-rich layer of ions, which inhibits the deuteron acceleration by shielding it from the field. When the proton layer is depleted, the deuterons become exposed to the space-charge field and are promptly accelerated. This scenario was tested with a two-dimensional particle-in-cell simulation model by varying the contaminant layer thickness and laser fluence (laser energy per unit area). For laser fluences F{sub laser}<1 J/{mu}m{sup 2}, the contamination layer over the surface inhibits the deuteron acceleration from the rear surface, while in the opposite case of laser fluences F{sub laser}>1 J/{mu}m{sup 2} deuterons and heavier ions can be successfully accelerated with conversion efficiency of laser energy into ions of more than 1%. Experimental data from a 6 {mu}m thick aluminum foil coated with a 1 {mu}m deuterated plastic layer on the back surface are suggestive of the detrimental role of contaminants on deuteron acceleration.

• OSTI ID: 21421289
• Journal Information: Physics of Plasmas, Vol. 17, Issue 10; Other Information: DOI: 10.1063/1.3497002; (c) 2010 American Institute of Physics; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ACCELERATION
ALUMINIUM
BEAM-PLASMA SYSTEMS
DEUTERONS
HEAVY IONS
LASER-PRODUCED PLASMA
LAYERS
LIGHT IONS
PLASMA SHEATH
PLASMA SIMULATION
SPACE CHARGE
TWO-DIMENSIONAL CALCULATIONS
WATER VAPOR
CHARGED PARTICLES
ELEMENTS
FLUIDS
GASES
IONS
METALS
PLASMA
SIMULATION
VAPORS