Feed-out of Rear Surface Perturbation due to Rarefaction Wave in Laser-Irradiated Targets

Shigemori, K.; Nakai, M.; Azechi, H.; Nishihara, Katsunobu; Ishizaki, R.; Nagaya, T.; Nagatomo, Hideo; Mima, Kunioki

doi:10.1103/physrevlett.84.5331

Cited by 23 publications

(14 citation statements)

References 22 publications

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“…This mechanism of RT seeding by a rippled rarefaction or expansion wave is called feedout. It has been studied in detail in planar geometry (Betti et al 1998b;Smitherman et al 1999;Shigemori et al 2000;Aglitskiy et al 2001bAglitskiy et al , 2002Velikovich et al 2001). Here is how the feedout proceeds.…”

Section: Feedoutmentioning

confidence: 99%

“…No room temperature facility is available for its experimental study. In an ICF experiment, launching a rarefaction wave is easy, it happens naturally when a radiation-driven shock wave breaks out at the rear surface of the target, as in Smitherman et al (1999), Shigemori et al (2000) and Aglitskiy et al (2001bAglitskiy et al ( , 2006). -The most important manifestation of the perturbation growth in a radially imploded ICF target is the lateral mass redistribution inside it that reduces the target uniformity and thus degrades the fusion neutron yield.…”

Section: Introductionmentioning

confidence: 99%

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Basic hydrodynamics of Richtmyer–Meshkov-type growth and oscillations in the inertial confinement fusion-relevant conditions

Aglitskiy

Velikovich

Karasik

et al. 2010

Phil. Trans. R. Soc. A.

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In inertial confinement fusion (ICF), the possibility of ignition or high energy gain is largely determined by our ability to control the Rayleigh-Taylor (RT) instability growth in the target. The exponentially amplified RT perturbation eigenmodes are formed from all sources of the target and radiation non-uniformity in a process called seeding. This process involves a variety of physical mechanisms that are somewhat similar to the classical Richtmyer-Meshkov (RM) instability (in particular, most of them are active in the absence of acceleration), but differ from it in many ways. In the last decade, radiographic diagnostic techniques have been developed that made direct observations of the RM-type effects in the ICF-relevant conditions possible. New experiments stimulated the advancement of the theory of the RM-type processes. The progress in the experimental and theoretical studies of such phenomena as ablative RM instability, re-shock of the RM-unstable interface, feedout and perturbation development associated with impulsive loading is reviewed.

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Section: Feedoutmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Basic hydrodynamics of Richtmyer–Meshkov-type growth and oscillations in the inertial confinement fusion-relevant conditions

Aglitskiy

Velikovich

Karasik

et al. 2010

Phil. Trans. R. Soc. A.

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“…As a result, these thinner parts evolve into bubbles, propagating ahead and dumping more of their mass into the spikes that trail behind, as predicted in [51] and observed in [52].…”

Section: Feedoutmentioning

confidence: 71%

“…Feedout is the physical mechanism responsible for the RT-seeding triggered by the roughness of the rear target surface [45,[51][52][53]. The RT growth begins after a shock wave initiated at the smooth irradiated surface of the target breaks out at its rippled inner (or rear, in planar geometry) surface, and a rippled rarefaction wave reflected from it reaches the front surface.…”

Section: Feedoutmentioning

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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“…259 In the context of the feedout problem, the oscillations were observed in simulations of hohlraum-driven experiments on Nova. 260 The first demonstration of feedout in a direct-drive configuration was reported by Shigemori et al 261 ( Fig. 7-15).…”

Section: Feedoutmentioning

confidence: 94%

Direct-drive inertial confinement fusion: A review

et al. 2015

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The direct-drive, laser-based approach to inertial confinement fusion (ICF) is reviewed from its inception following the demonstration of the first laser to its implementation on the present generation of high-power lasers. The review focuses on the evolution of scientific understanding gained from target-physics experiments in many areas, identifying problems that were demonstrated and the solutions implemented. The review starts with the basic understanding of laser–plasma interactions that was obtained before the declassification of laser-induced compression in the early 1970s and continues with the compression experiments using infrared lasers in the late 1970s that produced thermonuclear neutrons. The problem of suprathermal electrons and the target preheat that they caused, associated with the infrared laser wavelength, led to lasers being built after 1980 to operate at shorter wavelengths, especially 0.35 μm—the third harmonic of the Nd:glass laser—and 0.248 μm (the KrF gas laser). The main physics areas relevant to direct drive are reviewed. The primary absorption mechanism at short wavelengths is classical inverse bremsstrahlung. Nonuniformities imprinted on the target by laser irradiation have been addressed by the development of a number of beam-smoothing techniques and imprint-mitigation strategies. The effects of hydrodynamic instabilities are mitigated by a combination of imprint reduction and target designs that minimize the instability growth rates. Several coronal plasma physics processes are reviewed. The two-plasmon–decay instability, stimulated Brillouin scattering (together with cross-beam energy transfer), and (possibly) stimulated Raman scattering are identified as potential concerns, placing constraints on the laser intensities used in target designs, while other processes (self-focusing and filamentation, the parametric decay instability, and magnetic fields), once considered important, are now of lesser concern for mainline direct-drive target concepts. Filamentation is largely suppressed by beam smoothing. Thermal transport modeling, important to the interpretation of experiments and to target design, has been found to be nonlocal in nature. Advances in shock timing and equation-of-state measurements relevant to direct-drive ICF are reported. Room-temperature implosions have provided an increased understanding of the importance of stability and uniformity. The evolution of cryogenic implosion capabilities, leading to an extensive series carried out on the 60-beam OMEGA laser [Boehly et al., Opt. Commun. 133, 495 (1997)], is reviewed together with major advances in cryogenic target formation. A polar-drive concept has been developed that will enable direct-drive–ignition experiments to be performed on the National Ignition Facility [Haynam et al., Appl. Opt. 46(16), 3276 (2007)]. The advantages offered by the alternative approaches of fast ignition and shock ignition and the issues associated with these concepts are described. The lessons learned from target-physics and implosion experiments are taken into account in ignition and high-gain target designs for laser wavelengths of 1/3 μm and 1/4 μm. Substantial advances in direct-drive inertial fusion reactor concepts are reviewed. Overall, the progress in scientific understanding over the past five decades has been enormous, to the point that inertial fusion energy using direct drive shows significant promise as a future environmentally attractive energy source.

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Feed-out of Rear Surface Perturbation due to Rarefaction Wave in Laser-Irradiated Targets

Cited by 23 publications

References 22 publications

Basic hydrodynamics of Richtmyer–Meshkov-type growth and oscillations in the inertial confinement fusion-relevant conditions

Basic hydrodynamics of Richtmyer–Meshkov-type growth and oscillations in the inertial confinement fusion-relevant conditions

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

Direct-drive inertial confinement fusion: A review

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