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Title: Observation of Self-Similar Behavior of the 3D, Nonlinear Rayleigh-Taylor Instability

Abstract

The Rayleigh-Taylor unstable growth of laser-seededm 3D broadband perturbations was experimentally measured in the laser-seeded, planar plastic foils.

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Laboratory for Laser Energetics, University of Rochester, Rochester, NY
Sponsoring Org.:
USDOE
OSTI Identifier:
861893
Report Number(s):
DOE/SF/19460-644
1603; 2005-37
DOE Contract Number:
FC52-92SF19460
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 95
Country of Publication:
United States
Language:
English

Citation Formats

Sadot, O., Smalyuk, V.A., Delettrez, J. A., Meyerhofer, D.D., Sangster, T.C., Betti, R., Goncharov, V.N., and Shvarts, D. Observation of Self-Similar Behavior of the 3D, Nonlinear Rayleigh-Taylor Instability. United States: N. p., 2005. Web. doi:10.1103/PhysRevLett.95.265001.
Sadot, O., Smalyuk, V.A., Delettrez, J. A., Meyerhofer, D.D., Sangster, T.C., Betti, R., Goncharov, V.N., & Shvarts, D. Observation of Self-Similar Behavior of the 3D, Nonlinear Rayleigh-Taylor Instability. United States. doi:10.1103/PhysRevLett.95.265001.
Sadot, O., Smalyuk, V.A., Delettrez, J. A., Meyerhofer, D.D., Sangster, T.C., Betti, R., Goncharov, V.N., and Shvarts, D. Thu . "Observation of Self-Similar Behavior of the 3D, Nonlinear Rayleigh-Taylor Instability". United States. doi:10.1103/PhysRevLett.95.265001.
@article{osti_861893,
title = {Observation of Self-Similar Behavior of the 3D, Nonlinear Rayleigh-Taylor Instability},
author = {Sadot, O. and Smalyuk, V.A. and Delettrez, J. A. and Meyerhofer, D.D. and Sangster, T.C. and Betti, R. and Goncharov, V.N. and Shvarts, D.},
abstractNote = {The Rayleigh-Taylor unstable growth of laser-seededm 3D broadband perturbations was experimentally measured in the laser-seeded, planar plastic foils.},
doi = {10.1103/PhysRevLett.95.265001},
journal = {Physical Review Letters},
number = ,
volume = 95,
place = {United States},
year = {Thu Dec 29 00:00:00 EST 2005},
month = {Thu Dec 29 00:00:00 EST 2005}
}
  • The Rayleigh-Taylor unstable growth of laser-seeded, 3D broadband perturbations was experimentally measured in the laser-accelerated, planar plastic foils. The first experimental observation showing the self-similar behavior of the bubble size and amplitude distributions under ablative conditions is presented. In the nonlinear regime, the modulation {sigma}{sub rms} grows as {alpha}{sub {sigma}}gt{sup 2}, where g is the foil acceleration, t is the time, and {alpha}{sub {sigma}} is constant. The number of bubbles evolves as N(t){proportional_to}({omega}t{radical}(g)+C){sup -4} and the average size evolves as <{lambda}>(t){proportional_to}{omega}{sup 2}gt{sup 2}, where C is a constant and {omega}=0.83{+-}0.1 is the measured scaled bubble-merging rate.
  • The self-similar motion of a spherically symmetric isentropic cloud of ideal gas driven outward by an expanding low-density medium (e.g., radiation pressure from a pulsar) is shown to be unstable to Rayleigh-Taylor modes which develop in the neighborhood of the interface. A complete solution of the linearized equations of motion is obtained. The implications for astrophysical phenomena are discussed.
  • We report results from the first experiments to explore the evolution of the Rayleigh-Taylor (RT) instability from intentionally three-dimensional (3D) initial conditions at an embedded, decelerating interface in a high-Reynolds-number flow. The experiments used {approx}5 kJ of laser energy to produce a blast wave in polyimide and/or brominated plastic having an initial pressure of {approx}50 Mbars. This blast wave shocked and then decelerated the perturbed interface between first material and a lower-density, C foam. This caused the formation of a decelerating interface with an Atwood number {approx}2/3, producing a long-term positive growth rate for the RT instability. The initial perturbationsmore » were a 3D perturbation in an ''egg-crate'' pattern with feature spacings of 71 {micro}m in two orthogonal directions and peak-to-valley amplitudes of 5 {micro}m. The resulting RT spikes were observed to overtake the shock waves at the undisturbed, ''free-fall'' rate, and to subsequently deliver material from behind the interface to the forward shock. This result is unanticipated by prior simulations and models.« less