Strong stabilization of the Rayleigh-Taylor instability by material strength at megabar pressures
- Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
Experimental results showing significant reductions from classical in the Rayleigh-Taylor (RT) instability growth rate due to high pressure effective lattice viscosity in metal foils are presented. Stabilization of RT instability (RTI) by ablation and density gradients has been studied for decades. The regime of stabilized RTI due to material strength at high pressure is new. On the Omega Laser in the Laboratory for Laser Energetics, University of Rochester, target samples of polycrystalline vanadium are compressed and accelerated quasi-isentropically at approx1 Mbar pressures, while maintaining the samples in the solid-state. Provided strong shocks are avoided, the higher the applied peak pressure, the higher the predicted foil strength, and hence, the higher the degree of strength stabilization of RTI. Several experiments were conducted where the amount of RT growth is measured by face-on radiography. The vanadium samples are probed by a laser driven He-alpha x-ray backlighter which produced 5.2 keV radiation. Comparison of the results with constitutive models for solid state strength under these conditions show that the measured RT growth is substantially lower than predictions using existing models that work well at low pressures and long time scales. High pressure, high strain rate data can be explained by the enhanced strength due to a phonon drag mechanism, creating a high effective lattice viscosity.
- OSTI ID:
- 21371300
- Journal Information:
- Physics of Plasmas, Vol. 17, Issue 5; Other Information: DOI: 10.1063/1.3363170; (c) 2010 American Institute of Physics; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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EXPERIMENTAL TESTS OF VANADIUM STRENGTH MODELS AT HIGH PRESSURES AND STRAIN RATES
Strong stabilization of the Rayleigh-Taylor instability by material strength at Mbar pressures
Related Subjects
ABLATION
COMPRESSION STRENGTH
FOILS
INSTABILITY GROWTH RATES
LASERS
PHONONS
PLASMA DIAGNOSTICS
POLYCRYSTALS
RAYLEIGH-TAYLOR INSTABILITY
SHOCK WAVES
STABILIZATION
STRAIN RATE
VANADIUM
CRYSTALS
ELEMENTS
INSTABILITY
MECHANICAL PROPERTIES
METALS
QUASI PARTICLES
TRANSITION ELEMENTS