Details

Autor(en) / Beteiligte

• Poole, P L
• Obst, L
• Cochran, G E
• Metzkes, J
• Schlenvoigt, H-P
• Prencipe, I
• Kluge, T
• Cowan, T
• Schramm, U
• Schumacher, D W
• Zeil, K

Titel

Laser-driven ion acceleration via target normal sheath acceleration in the relativistic transparency regime

Ist Teil von

• New journal of physics, 2018-01, Vol.20 (1), p.13019

Ort / Verlag

Bristol: IOP Publishing

Erscheinungsjahr

2018

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• We present an experimental study investigating laser-driven proton acceleration via target normal sheath acceleration (TNSA) over a target thickness range spanning the typical TNSA-dominant regime (∼1 m) down to below the onset of relativistic laser-transparency (<40 nm). This is done with a single target material in the form of freely adjustable films of liquid crystals along with high contrast (via plasma mirror) laser interaction (∼2.65 J, 30 fs, I > 1 × 10 21 W cm−2). Thickness dependent maximum proton energies scale well with TNSA models down to the thinnest targets, while those under ∼40 nm indicate the influence of relativistic transparency on TNSA, observed via differences in light transmission, maximum proton energy, and proton beam spatial profile. Oblique laser incidence (45°) allowed the fielding of numerous diagnostics to determine the interaction quality and details: ion energy and spatial distribution was measured along the laser axis and both front and rear target normal directions; these along with reflected and transmitted light measurements on-shot verify TNSA as dominant during high contrast interaction, even for ultra-thin targets. Additionally, 3D particle-in-cell simulations qualitatively support the experimental observations of target-normal-directed proton acceleration from ultra-thin films.