Experimental Study of Laser Driven Compression of Spherical Glass Shells

Charatis, G.; Downward, J. G.; Goforth, R. R.; Guscott, B. R.; Henderson, Thomas M.; Hildum, S.; Johnson, R. R.; Moncur, Kent; Leonard, Thomas A.; Meyer, F. P.; Segall, S. B.; Siebert, L. D.; Solomon, Deepak E.; Thomas, Ciza

doi:10.2184/lsj.2.3_213

Cited by 8 publications

(14 citation statements)

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“…The next major step forward came with the demonstration at KMS Fusion of thermonuclear neutrons resulting from laser-induced compression, reported by Johnson et al 89 and Charatis et al 90 A schematic of this experiment is shown in Fig. 4-3(a).…”

Section: A the Quest For Neutronsmentioning

confidence: 99%

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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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Section: A the Quest For Neutronsmentioning

confidence: 99%

“…452 who found maximum gain for scattering through 90 , a result for which no experimental evidence ever seems to have been offered.…”

Section: B Stimulated Brillouin Scattering (Sbs) and Crossbeam Energmentioning

confidence: 99%

Direct-drive inertial confinement fusion: A review

et al. 2015

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“…With a suitably in tense laser beam and proper target construction, it was proposed that economical laser-induced nuclear fusion was feasible. 3 " 5 This was followed by an experimental demonstration of laser fusion at KMS Fusion Inc.. Ann Arbor, Ml, 6 at LLL, 7 and elsewhere. 8 With the laser's invention in 1958, 9 national programs began, which have supported its development to the present, relatively well-understood experimental state.…”

Section: L2mentioning

confidence: 99%

“…This requires a gain of ~I0 6 . Additional small-signal gain is required to overcome fixed losses and saturation.…”

Section: Gain Constraintsmentioning

confidence: 99%