Effect of barrier layers in burnthrough experiments with 351-nm laser illumination

Journal Article · Tue May 15 04:00:00 EDT 1990 · Physical Review, A (General Physics); (USA)

DOI:https://doi.org/10.1103/PhysRevA.41.5583· OSTI ID:6800430

Delettrez, J; Bradley, D K; Jaanimagi, P A; Verdon, C P ^[1]

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1. Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (US)

The time-resolved x-ray emission is measured from spherical targets consisting of glass shells overcoated with plastic in which thin signature layers are embedded. These targets are illuminated at 351 nm by the 24-beam OMEGA laser system at the Laboratory for Laser Energetics of the University of Rochester. We measure a large burnthrough rate for bare plastic targets that can only be replicated in one-dimensional hydrodynamic simulations with laser intensities in excess of ten times the nominal intensity. We observe that the burnthrough times are affected by the presence of a thin outer coating (barrier layer). The burnthrough times depend strongly on the barrier-layer material and thickness, whereas one-dimensional simulation results predict only a small effect. Several processes are considered to explain these results: illumination nonuniformity, early shinethrough of the laser light through the plastic, prepulses, filamentation, self-focusing of hot spots, and the Rayleigh-Taylor instability. We conclude that mixing due to the Rayleigh-Taylor instability, enhanced by early shinethrough, is the most probable cause of the observed large burnthrough rates.

• DOE Contract Number: FC03-85DP40200
• OSTI ID: 6800430
• Journal Information: Physical Review, A (General Physics); (USA), Journal Name: Physical Review, A (General Physics); (USA) Vol. 41:10; ISSN PLRAA; ISSN 0556-2791
• Country of Publication: United States
• Language: English

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BOUNDARY LAYERS
CHEMICAL ANALYSIS
CONFIGURATION
CONFINEMENT
IMPLOSIONS
INERTIAL CONFINEMENT
INSTABILITY
LASER IMPLOSIONS
LASER TARGETS
LAYERS
NONDESTRUCTIVE ANALYSIS
OMEGA FACILITY
PLASMA CONFINEMENT
RAYLEIGH-TAYLOR INSTABILITY
RESOLUTION
SPHERICAL CONFIGURATION
TARGETS
TIME RESOLUTION
TIMING PROPERTIES
TRACE AMOUNTS
X-RAY EMISSION ANALYSIS