Large growth, planar Rayleigh--Taylor experiments on Nova

Journal Article · Wed Apr 01 00:00:00 EST 1992 · Physics of Fluids B; (United States)

DOI:https://doi.org/10.1063/1.860113· OSTI ID:7233924

Remington, B A; Haan, S W; Glendinning, S G; Kilkenny, J D; Munro, D H; Wallace, R J ^[1]

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1. Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

A set of indirect-drive experiments to study large growth Rayleigh--Taylor instability using shaped laser pulses at the Nova laser facility has been conducted. Planar foils of fluorosilicone were accelerated by x-ray ablation. The foil trajectory was measured using edge-on radiography. In separate experiments using face-on radiography, contrast in optical depth was measured as a function of time, from which the evolution of 50 {mu}m wavelength initially sinusoidal surface perturbations was deduced. Holding other parameters fixed, the amplitude of the initial perturbation was varied by up to a factor of 30 in separate shots. The foils with the smallest initial perturbation exhibited growth factors of 75 in contrast. Foils with large initial amplitude perturbation gave growth factors of 6 or less, and displayed the bubble-and-spike'' shape characteristic of the nonlinear Rayleigh--Taylor instability. Comparisons of two-dimensional computer simulations with both the measured foil trajectory and the perturbation growth show good agreement, provided that a suitable opacity model is chosen. In the linear regime the observed growth rates are 60%--75% of classical, the reduction attributed primarily to ablative stabilization. The observed onset of harmonic generation, signaling the transition into the nonlinear regime, is well predicted by third-order theory.

• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 7233924
• Journal Information: Physics of Fluids B; (United States), Vol. 4:4; ISSN 0899-8221
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
NOVA FACILITY
RAYLEIGH-TAYLOR INSTABILITY
ABLATION
COMPUTERIZED SIMULATION
FLUORINE COMPOUNDS
FOILS
HARMONIC GENERATION
IMPLOSIONS
INSTABILITY GROWTH RATES
PLASMA CONFINEMENT
PLASMA MACROINSTABILITIES
PLASMA SIMULATION
SILICON COMPOUNDS
STABILIZATION
X RADIATION
CONFINEMENT
ELECTROMAGNETIC RADIATION
FREQUENCY MIXING
HALOGEN COMPOUNDS
INSTABILITY
IONIZING RADIATIONS
PLASMA INSTABILITY
RADIATIONS
SIMULATION
700340* - Plasma Waves
Oscillations
& Instabilities- (1992-)