Bulletin of the American Physical Society
58th Annual Meeting of the APS Division of Plasma Physics
Volume 61, Number 18
Monday–Friday, October 31–November 4 2016; San Jose, California
Session UI3: ICF: Implosion Drive
2:00 PM–5:00 PM,
Thursday, November 3, 2016
Room: 210 ABEF
Chair: Kyle Peterson, Sandia National Laboratories
Abstract ID: BAPS.2016.DPP.UI3.1
Abstract: UI3.00001 : Progress towards a one-dimensional layered DT implosion using HDC capsules at the NIF*
2:00 PM–2:30 PM
Preview Abstract Abstract
(Lawrence Livermore National Laboratory)
Using a 0.8x scale HDC capsule (D=1.6 mm) in a full scale DU hohlraum (D=5.75 mm) filled with relatively low He gas (0.3mg/cc), we have been able to achieve a high (C=26) convergence layered DT implosion that is diagnosed within 10 percent of round at all measured times. An adiabat-2.5, 3-shock, 1MJ-7ns laser pulse was used to achieved velocities $>$350 km/s, neutron yield $\approx$ 3e15 with a down scattered ratio $\approx$ 0.03. This platform shows minimal laser plasma interaction (no measurable hot electrons, $> 97\%$ coupling, no cross beam energy transfer required). A direct control of the laser cone fraction vs. time was used to obtain 3-shock-breakout symmetry (keyhole target), in flight symmetry (radiography at convergence 2-4) and symmetric hot spot/rebound shock at convergence 12 (gas-filled capsule) and 26 (layered DT). Further repointing of laser cones demonstrated control of higher modes (P4). 4 layered DT implosions allowed to compare the effect of W-dopant, symmetry and velocity on performance. We will show using experimental results and simulations that the W-doped HDC implosion behaves as expected and reaches 40$\%$ of Yield Over Clean (YOC), with the fill-tube perturbation being a possible cause of the reduced yield. The undoped HDC capsule has a YOC $<$ 0.3, showing more sensitivity to X-ray preheat than expected. The path towards an equivalent scale 1 implosion capable of large alpha-heating will be discussed.
*This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2016.DPP.UI3.1
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