Measurements of preheat and shock melting in Be ablators during the first few nanoseconds of a National Ignition Facility ignition drive using the Omega laser
- Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550 (United States)
- General Atomics, San Diego, California 92186 (United States)
A scaled Hohlraum platform was used to experimentally measure preheat in ablator materials during the first few nanoseconds of a radiation drive proposed for ignition experiments at the National Ignition Facility [J. A. Paisner et al., Laser Focus World 30, 75 (1994)]. The platform design approximates the radiation environment of the pole of the capsule by matching both the laser spot intensity and illuminated Hohlraum wall fraction in scaled halfraums driven by the OMEGA laser system [T. R. Boehly et al., Opt. Commun. 133, 495 (1997)]. Back surface motion measured via VISAR reflecting from the rear surface of the sample was used to measure sample motion prior to shock breakout. The experiments show that the first {approx}20 {mu}m of a Be ablator will be melted by radiation preheat, with subsequent material melted by the initial shock, in agreement with simulations. The experiments also show no evidence of anomalous heating of buried high-Z doped layers in the ablator.
- OSTI ID:
- 21277014
- Journal Information:
- Physics of Plasmas, Vol. 16, Issue 4; Other Information: DOI: 10.1063/1.3104702; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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