Two mode coupling of the ablative Rayleigh-Taylor instabilities

Xin, Jiyu; Yan, Rui; Wan, Zhen-Hua; Sun, Daoyuan; Zheng, Jian; Zhang, H.; Aluie, Hussein; Betti, R.

doi:10.1063/1.5070103

Cited by 21 publications

(7 citation statements)

References 26 publications

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“…3, the transition happens at earlier times for bi-mode targets (around 40 ns). This difference might be due to the enhancement of non-linear effects and mode coupling of a multi-wavelength perturbations 41 . This phenomenon is highlighted on the 20 ns radiograph.…”

Section: Resultsmentioning

confidence: 99%

Micron-scale phenomena observed in a turbulent laser-produced plasma

et al. 2021

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Turbulence is ubiquitous in the universe and in fluid dynamics. It influences a wide range of high energy density systems, from inertial confinement fusion to astrophysical-object evolution. Understanding this phenomenon is crucial, however, due to limitations in experimental and numerical methods in plasma systems, a complete description of the turbulent spectrum is still lacking. Here, we present the measurement of a turbulent spectrum down to micron scale in a laser-plasma experiment. We use an experimental platform, which couples a high power optical laser, an x-ray free-electron laser and a lithium fluoride crystal, to study the dynamics of a plasma flow with micrometric resolution (~1μm) over a large field of view (>1 mm2). After the evolution of a Rayleigh–Taylor unstable system, we obtain spectra, which are overall consistent with existing turbulent theory, but present unexpected features. This work paves the way towards a better understanding of numerous systems, as it allows the direct comparison of experimental results, theory and numerical simulations.

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Section: Resultsmentioning

confidence: 99%

Micron-scale phenomena observed in a turbulent laser-produced plasma

et al. 2021

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“…This can have severe adverse effects on the ICF target performance [30,31,32,33,3]. Recent experiments and numerical simulations [34,35,36,37,38,39,40,41,42] have shown that even the prediction of a terminal bubble velocity breaks down at late times. In ablative RTI, it was found that the bubble is accelerated to velocities above the potential flow prediction after a quasi constant-velocity phase [34].…”

Section: Introductionmentioning

confidence: 99%

Revisiting the late-time growth of single-mode Rayleigh–Taylor instability and the role of vorticity

Bian

Aluie

Zhao

et al. 2020

Physica D: Nonlinear Phenomena

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Growth of the single-fluid single-mode Rayleigh-Taylor instability (RTI) is revisited in 2D and 3D using fully compressible high-resolution simulations. We conduct a systematic analysis of the effects of perturbation Reynolds number (Re p ) and Atwood number (A) on RTI's late-time growth. Contrary to the common belief that single-mode RTI reaches a terminal bubble velocity, we show that the bubble re-accelerates when Re p is sufficiently large, consistent with [Ramaparabhu et al. 2006, Wei andLivescu 2012]. However, unlike in [Ramaparabhu et al. 2006], we find that for a sufficiently high Re p , the bubble's late-time acceleration is persistent and does not vanish. Analysis of vorticity dynamics shows a clear correlation between vortices inside the bubble and re-acceleration. Due to symmetry around the bubble and spike (vertical) axes, the self-propagation velocity of vortices points in the vertical direction. If viscosity is sufficiently small, the vortices persist long enough to enter the bubble tip and accelerate the bubble [Wei and Livescu 2012]. A similar effect has also been observed in ablative RTI [Betti and Sanz 2006]. As the spike growth increases relative to that of the bubble at higher A, vorticity production shifts downward, away from the centerline and toward the spike tip. We modify the Betti-Sanz model for bubble velocity by introducing a vorticity efficiency factor η = 0.45 to accurately account for re-acceleration caused by vorticity in the bubble tip. It had been previously suggested that vorticity generation and the associated bubble re-acceleration are suppressed at high A. However, we present evidence that if the large Re p limit is taken first, bubble re-acceleration is still possible. Our results also show that re-acceleration is much easier to occur in 3D than 2D, requiring smaller Re p thresholds.

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“…Most researchers deal with classical RTI model of two semi-infinity fluids with a single-interface. [6][7][8][9][10][11] However, we want to investigate an accelerated thin shell in ICF implosion. How perturbations on one interface are transmitted to another interface is a critical issue for ICF implosion.…”

Section: Introductionmentioning

confidence: 99%

Effect of initial phase on the Rayleigh–Taylor instability of a finite-thickness fluid shell

Guo¹,

Cheng²,

Li³

et al. 2022

Chinese Phys. B

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Rayleigh–Taylor instability (RTI) of finite-thickness shell plays an important role in deep understanding the characteristics of shell deformation and material mixing. The RTI of a finite-thickness fluid layer is studied analytically considering an arbitrary perturbation phase difference on the two interfaces of the shell. The third-order weakly nonlinear (WN) solutions for RTI are derived. It is found the main feature (bubble-spike structure) of the interface is not affected by phase difference. However, the positions of bubble and spike are sensitive to the initial phase difference, especially for a thin shell (kd < 1), which will be detrimental to the integrity of the shell. Furthermore, the larger phase difference results in much more serious RTI growth, significant shell deformation can be obtained in the WN stage for perturbations with large phase difference. Therefore, it should be considered in applications where the interface coupling and perturbation phase effects are important, such as inertial confinement fusion.

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Two mode coupling of the ablative Rayleigh-Taylor instabilities

Cited by 21 publications

References 26 publications

Micron-scale phenomena observed in a turbulent laser-produced plasma

Micron-scale phenomena observed in a turbulent laser-produced plasma

Revisiting the late-time growth of single-mode Rayleigh–Taylor instability and the role of vorticity

Effect of initial phase on the Rayleigh–Taylor instability of a finite-thickness fluid shell

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