1. 2D X-ray radiography of imploding capsules at the national ignition facility.
- Author
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Rygg JR, Jones OS, Field JE, Barrios MA, Benedetti LR, Collins GW, Eder DC, Edwards MJ, Kline JL, Kroll JJ, Landen OL, Ma T, Pak A, Peterson JL, Raman K, Town RP, and Bradley DK
- Subjects
- Computer Simulation, Germanium chemistry, Gold chemistry, Thermodynamics, X-Rays, Models, Theoretical, Radiography methods
- Abstract
First measurements of the in-flight shape of imploding inertial confinement fusion (ICF) capsules at the National Ignition Facility (NIF) were obtained by using two-dimensional x-ray radiography. The sequence of area-backlit, time-gated pinhole images is analyzed for implosion velocity, low-mode shape and density asymmetries, and the absolute offset and center-of-mass velocity of the capsule shell. The in-flight shell is often observed to be asymmetric even when the concomitant core self-emission is round. A ∼ 15 μm shell asymmetry amplitude of the Y(40) spherical harmonic mode was observed for standard NIF ICF hohlraums at a shell radius of ∼ 200 μm (capsule at ∼ 5× radial compression). This asymmetry is mitigated by a ∼ 10% increase in the hohlraum length.
- Published
- 2014
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