Observation of Rayleigh–Taylor growth to short wavelengths on Nike

Pawley, C. J.; Bodner, S. E.; Dahlburg, J. P.; Obenschain, S. P.; Schmitt, A. J.; Sethian, J. D.; Sullivan, C. A.; Gardner, John; Aglitskiy, Y.; Chan, Y.; Lehecka, T.

doi:10.1063/1.873201

Cited by 58 publications

(23 citation statements)

References 31 publications

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“…This is the most straightforward situation to produce, to diagnose, and to simulate. In the realm of highenergy-density systems, this has included many studies of RT behavior at an ablation surface, [3][4][5] motivated by inertial fusion, and a number of studies [6][7][8][9][10][11][12][13][14] of RT behavior at a decelerating, embedded interface, motivated by basic science and/or astrophysics. In recent work with decelerating-interface experiments, buoyancy-drag models have proven successful, after adjusting for compressibility effects, in explaining observations with single-mode perturbations and 2D simulations have proven able to reproduce, on the whole, observations with 2D multimode perturbations.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear mixing behavior of the three-dimensional Rayleigh–Taylor instability at a decelerating interface

et al. 2004

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We report results from the first experiments to explore the evolution of the RayleighTaylor (RT) instability from intentionally three-dimensional (3D) initial conditions at an embedded, decelerating interface in a high-Reynolds-number flow. The experiments used 5 kJ of laser energy to produce a blast wave in polyimide and/or brominated plastic having an initial pressure of ~ 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 ~2/3, producing a longterm positive growth rate for the RT instability. The initial perturbations were a 3D perturbation in an "egg-crate" pattern with feature spacings of 71 µm in two orthogonal directions and peak-to-valley amplitudes of 5 µm. 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.

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Section: Introductionmentioning

confidence: 99%

Nonlinear mixing behavior of the three-dimensional Rayleigh–Taylor instability at a decelerating interface

et al. 2004

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“…In our experiments on Nike and elsewhere we successfully used crystal -spectral line "matching pairs" that cover X-ray energies from 0.6 to 8 keV. In the series of experiments described here we were using 1.86 keV probing energy which was hard enough to study 40 μm to 90 μm thick plastic (CH) targets either flat or rippled with perturbation wavelength λ ranging from 12.5 to 60 μm [38]. Also shown on a Fig.1 is close-fitting light baffle with an aperture stop just larger than the size of the backlighter image that has been placed in the reflected beam to block most of the continuum radiation from the plastic target.…”

Section: Diagnostics Descriptionmentioning

confidence: 99%

Classical and ablative Richtmyer–Meshkov instability and other ICF-relevant plasma flows diagnosed with monochromatic x-ray imaging

et al. 2008

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Abstract. In inertial confinement fusion (ICF) and high-energy density physics (HEDP), the most important manifestations of the hydrodynamic instabilities and other mixing processes involve lateral motion of the accelerated plasmas. In order to understand the experimental observations and to advance the numerical simulation codes to the point of predictive capability, it is critically important to accurately diagnose the motion of the dense plasma mass. The most advanced diagnostic technique recently developed for this purpose is the monochromatic x-ray imaging that combines large field of view with high contrast, high spatial resolution and large throughput, ensuring high temporal resolution at large magnification. Its application made it possible for the experimentalists to observe for the first time important hydrodynamic effects that trigger compressible turbulent mixing in laser targets, such as ablative Richtmyer-Meshkov (RM) instability, feedout, interaction of a RMunstable interface with rarefaction waves. It also helped to substantially improve the accuracy of diagnosing many other important plasma flows, ranging from laser-produced jets to electromagnetically driven wires in a Z-pinch, and to test various methods suggested for mitigation of the Rayleigh-Taylor instability. We will review the results obtained with the aid of this technique in ICF-HEDP studies at the Naval Research Laboratory and the prospects of its future applications.

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“…It was accelerated by a two-step 1-THz pulse from the Nike laser, composed of a 4 ns main pulse at about 8 × 10 13 W/cm 2 preceded by a ∼4 ns foot at about 5% of the main intensity. X-ray framing cameras recorded emission from a backlighter that was created by illuminating a Mg sample with 12 Nike beams [17].…”

Section: Multimode Simulations and Rayleigh-taylor Growthmentioning

confidence: 99%

Growth of pellet imperfections and laser imprint in direct drive inertial confinement fusion targets

et al. 2001

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Simple hydrodynamic models for describing the Richtmyer-Meshkov (RM) growth and the Rayleigh-Taylor (RT) instability are tested by simulation.The RM sharp boundary model predictions are compared with numerical simulations of targets with surface perturbations or stationary intensity perturbations. Agreement is found in the overall trends, but the specific behavior can be significantly different. RM growth of imprint from optically smoothed lasers is also simulated and quantified. The results are used to calculate surface perturbations, growth factors, and laser imprint efficiencies. These in turn are used with standard RT growth formulas to predict perturbation growth in multimode simulations of compression and acceleration of planar and spherical targets. The largest differences between prediction and theory occur during ramp-up of the laser intensity, where RT formulas predict more growth than seen in the simulations.

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Observation of Rayleigh–Taylor growth to short wavelengths on Nike

Cited by 58 publications

References 31 publications

Nonlinear mixing behavior of the three-dimensional Rayleigh–Taylor instability at a decelerating interface

Nonlinear mixing behavior of the three-dimensional Rayleigh–Taylor instability at a decelerating interface

Classical and ablative Richtmyer–Meshkov instability and other ICF-relevant plasma flows diagnosed with monochromatic x-ray imaging

Growth of pellet imperfections and laser imprint in direct drive inertial confinement fusion targets

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