Plasma density scale length determination in a deuterium, laser generated plasma

Saleres, A.; Decroisette, M.; Patou, C.

doi:10.1016/0030-4018(75)90110-8

Cited by 19 publications

(3 citation statements)

References 4 publications

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“…L'émission à 2 coo [12,13] apparaît au voisinage de la densité critique où s'effectue l'absorption du rayonnement laser. L'émission X permet de suivre le mouvement de la région chaude et suffisamment dense de la zone de conduction, située entre la surface critique et l'arrière du front de choc.…”

Section: Optimisation De L'efficacité D'absorptionunclassified

Résultats de l'expérience à 4 faisceaux en irradiation sphérique à Limeil

Billon

Holstein

Launspach

et al. 1977

Rev. Phys. Appl. (Paris)

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Section: Optimisation De L'efficacité D'absorptionunclassified

Résultats de l'expérience à 4 faisceaux en irradiation sphérique à Limeil

Billon

Holstein

Launspach

et al. 1977

Rev. Phys. Appl. (Paris)

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“…X A), comes from quarter critical.] Timeintegrated images of the 2x 0 and 3x 0 =2 emissions were first reported by Saleres et al 131 for solid D 2 targets. An interferometric measurement of the density profile was obtained by Attwood et al 132 for the one-sided irradiation of 40-lm-diam glass microballoons with 30-ps pulses at $3 Â 10 14 W/cm 2 .…”

Section: Plasma Diagnosticsmentioning

confidence: 99%

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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“…These results have permitted the determination of some macroscopic plasma parameters, such as the focal spot diameter or the electron density scale length [10][11][12]. Of even greater interest is the insight into the interaction processes of intense laser light with plasma which is provided by such measurements.…”

mentioning

confidence: 99%

Spectral analysis of backreflected light and harmonic generation in a co2 laser-target interaction experiment

et al. 1978

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2014 Dans des expériences d'interaction laser CO2-cible solide, nous avons étudié le spectre de la lumière réfléchie ou réfractée à la fréquence fondamentale du laser ou à ses harmoniques. L'analyse du spectre à la fréquence fondamentale fait apparaitre une raie déplacée vers le rouge qui est interprétée comme due à la rétrodiffusion Brillouin stimulée et qui correspond à une faible fraction de la lumière rétrodiffusée. Les harmoniques 2 03C9 et 3/2 03C9 ainsi que leurs spectres ont été observés; leur génération montre la présence d'instabilités paramétriques telles que la décomposition paramétrique ou l'instabilité deux plasmons dans l'interaction laser-plasma. Les harmoniques permettent de plus, d'accéder à la mesure locale de certains paramètres du plasma, tels que la température électronique et la grandeur caractéristique du gradient de densité.

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Plasma density scale length determination in a deuterium, laser generated plasma

Cited by 19 publications

References 4 publications

Résultats de l'expérience à 4 faisceaux en irradiation sphérique à Limeil

Résultats de l'expérience à 4 faisceaux en irradiation sphérique à Limeil

Direct-drive inertial confinement fusion: A review

Spectral analysis of backreflected light and harmonic generation in a co2 laser-target interaction experiment

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