High Power Laser Science and Engineering, 2015, 3 (3): 03000001, Published Online: Jan. 7, 2016
Measurements of the ablation-front trajectory and low-mode nonuniformity in direct-drive implosions using x-ray self-emission shadowgraphy 
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low mode nonuiformity low mode nonuiformity nuclear fusion nuclear fusion self-emission shadowgraphy self-emission shadowgraphy shell trajectory shell trajectory
Abstract
Self-emission x-ray shadowgraphy provides a method to measure the ablation-front trajectory and low-mode nonuniformity of a target imploded by directly illuminating a fusion capsule with laser beams. The technique uses time-resolved images of soft x-rays (>1 keV) emitted from the coronal plasma of the target imaged onto an x-ray framing camera to determine the position of the ablation front. Methods used to accurately measure the ablation-front radius (δR=±1.15 μm), image-to-image timing (δ(Δt)=±2.5 ps) and absolute timing (δt=±10 ps) are presented. Angular averaging of the images provides an average radius measurement of δ(Rav=±0.15 μm and an error in velocity of δV/V= ±3%. This technique was applied on the Omega Laser Facility [Boehly et al., Opt. Commun. 133, 495 (1997)] and the National Ignition Facility [Campbell and Hogan, Plasma Phys. Control. Fusion 41, B39 (1999)].
D.T. Michel , D.T. Michel , W. Armstrong, R. Bahr , R. Epstein , V.N. Goncharov, M. Hohenberger , I.V. Igumenshchev , R. Jungquist , D.D. Meyerhofer , P.B. Radha , T.C. Sangster , C. Sorce , D.H. Froula . Measurements of the ablation-front trajectory and low-mode nonuniformity in direct-drive implosions using x-ray self-emission shadowgraphy[J]. High Power Laser Science and Engineering, 2015, 3(3): 03000001.
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