Laser Driven Implosion Experiments at Limeil

Billon, D.; Holstein, P.A.; Launspach, J.; Patou, C.; Reisse, Jacques; Schirmann, D.

doi:10.1007/978-1-4684-8103-7_27

Cited by 9 publications

(5 citation statements)

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“…The best experimental neutron yields (a few 10 6 ) obtained with AR = 0.68 /xm at $i = 2 X 10 l s W-cnT 2 , consistent with a pure explosive-pusher analytical model [7], appear to correspond to highest transmissions, i.e. to the most pronounced temperature uniformities.…”

Section: Fig2 Experimental and Calculated Transmissions For Bare And ...mentioning

confidence: 55%

“…Experiments were performed by using the eight-beam Nd-glass laser facility Octal (0.8 TW, 50 ps). To ensure isotropic energy deposition, the target irradiation was performed with beams coming in along the cubic diagonal directions [7]. Standard targets were glass microballoons (2R = 80 nm diameter, AR = 0.7 jim wall thickness); thicker targets were obtained by C 8 H 10 (p-xylene) plastic coating with wall thicknesses up to 7 nm.…”

Section: Referencesmentioning

confidence: 99%

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A study of exploding-pusher laser-induced implosions using X-ray backlighting

et al. 1981

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Section: Fig2 Experimental and Calculated Transmissions For Bare And ...mentioning

confidence: 55%

Section: Referencesmentioning

confidence: 99%

A study of exploding-pusher laser-induced implosions using X-ray backlighting

et al. 1981

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“…It became possible to follow the implosion continuously, through the compression and disassembly phases, based on the self-emission of the target. Streaked x-ray imaging of imploding targets was also reported by Billon et al 137 Another advance, with far-reaching significance, was the development of x-ray backlighting at the Rutherford Laboratory using the Vulcan laser. This was reported by Key et al,138 who used the configuration shown in Fig.…”

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confidence: 67%

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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“…Several laboratories have carried out so-called 'transition' implosion experiments in which lengthening NUCLEAR FUSION, Vol.24, No.5 (1984) the pulse duration and coating the microballoon wall have made it possible to obtain a more ablative regime, thus producing higher densities than in the explodingpusher regime [27][28][29][30][31][32]. The first work at the Centre d'etudes de Limeil-Valenton in this field was performed in 1976 with the C6 Nd-laser irradiating DLi microspheres or neon-filled microballoons in tetrahedral geometry [33].…”

Section: Introductionmentioning

confidence: 99%

Laser implosion of microballoons: study of the transition from exploding-pusher to ablative regime

et al. 1984

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Microballoons filled with an equimolar deuterium-tritium mixture and coated with a plastic ablator of variable thickness are imploded by the eight-beam Octal laser (X = 1.06 jum; 0.6 TW). An X-ray r diagnostic with space-time resolution is used to analyse the implosion of the targets designed to the highest /pdr. The experimental results are compared with numerical simulations performed by a one-dimensional J Lagrangian code. A DT density of about 2 gem" 3 is obtained; the transition from an exploding-pusher regime to a more ablative one is analysed on the basis of the evolution of the preheat, the hydrodynamic efficiency and the density and temperature performance.

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Laser Driven Implosion Experiments at Limeil

Cited by 9 publications

References 1 publication

A study of exploding-pusher laser-induced implosions using X-ray backlighting

A study of exploding-pusher laser-induced implosions using X-ray backlighting

Direct-drive inertial confinement fusion: A review

Laser implosion of microballoons: study of the transition from exploding-pusher to ablative regime

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