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Title: High-density carbon ablator experiments on the National Ignition Facilitya)

High Density Carbon (HDC) is a leading candidate as an ablator material for Inertial Confinement Fusion (ICF) capsules in x-ray (indirect) drive implosions. HDC has a higher density (3.5 g/cc) than plastic (CH, 1 g/cc), which results in a thinner ablator with a larger inner radius for a given capsule scale. This leads to higher x-ray absorption and shorter laser pulses compared to equivalent CH designs. This paper will describe a series of experiments carried out to examine the feasibility of using HDC as an ablator using both gas filled hohlraums and lower density, near vacuum hohlraums. These experiments have shown that deuterium (DD) and deuterium-tritium gas filled HDC capsules driven by a hohlraum filled with 1.2 mg/cc He gas, produce neutron yields a factor of 2× higher than equivalent CH implosions, representing better than 50% Yield-over-Clean (YoC). In a near vacuum hohlraum (He = 0.03 mg/cc) with 98% laser-to-hohlraum coupling, such a DD gas-filled capsule performed near 1D expectations. A cryogenic layered implosion version was consistent with a fuel velocity = 410 ± 20 km/s with no observed ablator mixing into the hot spot.
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  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States)
  3. Univ. of Rochester, NY (United States)
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  5. General Atomics, San Diego, CA (United States)
  6. Diamond Materials GmbH, Freiburg (Germany)
Publication Date:
OSTI Identifier:
1165740
DOE Contract Number:
DE-AC52-07NA27344
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 5
Publisher:
American Institute of Physics (AIP)
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING PHYSICS OF PLASMA; HYDRODYNAMICS SIMULATIONS; HOHLRAUM