Target design for ignition experiments on the laser Mégajoule facility

Giorla, J.; Bastian, Johannes Dominik; Bayer, C.; Canaud, B.; Casanova, M.; Chaland, F.; Cherfils, C.; Clique, C.; Dattolo, E.; Fremerye, P.; Galmiche, D.; Garaude, F.; Gauthier, P.; Laffite, S.; Lecler, N; Liberatore, S.; Loiseau, P.; Malinie, G.; Massé, L.; Masson, A.; Monteil, M. C.; Poggi, F.; Quach, Robert; Renaud, François; Saillard, Yves; Seytor, P.; Vandenboomgaerde, M.; Vliet, Jan van der; Wagon, F.

doi:10.1088/0741-3335/48/12b/s07

Cited by 31 publications

(22 citation statements)

References 17 publications

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“…Assuming relatively small láser beams, with surfaces of about 10 2 -15 2 cm 2 and máximum energy fluence of 1 -=-3 J/cm 2 , it turns out that a total of a few thousand beamlets should be used to provide a total energy of about 1 MJ. These beamlets should be grouped in bundles which surface would be of about 1 -1.5 m 2 (which is roughly the double of a quad in the National Ignition Facility [12] in the USA or the Láser MegaJoule [13] . Moreover, the large number of beamlets is also useful in order to use the zooming technique [14] where different focal spots are used to optimize the laser-capsule coupling preserving the irradiation uniformity of the capsule [15].…”

Section: Introductionmentioning

confidence: 99%

Stochastic homogenization of the laser intensity to improve the irradiation uniformity of capsules directly driven by thousands laser beams

Temporal

Canaud

2011

Eur. Phys. J. D

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Abstract. Illumination uniformity of a spherical capsule directly driven by láser beams has been assessed numerically. Láser facilities characterized by ND = 12, 20, 24, 32, 48 and 60 directions of irradiation with associated a single láser beam or a bundle of NB láser beams have been considered. The láser beam intensity profile is assumed super-Gaussian and the calculations take into account beam imperfections as power imbalance and pointing errors. The optimum láser intensity profile, which minimizes the root-meansquare deviation of the capsule illumination, depends on the valúes of the beam imperfections. Assuming that the NB beams are statistically independents is found that they provide a stochastic homogenization of the láser intensity associated to the whole bundle, reducing the errors associated to the whole bundle by the factor 1/N B , which in turn improves the illumination uniformity of the capsule. Moreover, it is found that the uniformity of the irradiation is almost the same for all facilities and only depends on the total number of láser beams Not = ND X NB •

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Section: Introductionmentioning

confidence: 99%

Stochastic homogenization of the laser intensity to improve the irradiation uniformity of capsules directly driven by thousands laser beams

Temporal

Canaud

2011

Eur. Phys. J. D

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“…Present laser facilities designed for ICF study almost all operate at blue light (3ω), such as the National Ignition Facility [2], the Shenguang series [3,4], the OAMEG [5] and the Laser Mégajoule facility [6], because 3ω has the advantages of a higher laser deposition [7,8] and a lower LPI [9] than green light (2ω). However, 3ω is generated via the frequency-tripling technique with a relatively low efficiency, and in addition, it has a relatively low damage threshold for the optic components in the final optic assembly [10].…”

Section: Introductionmentioning

confidence: 99%

Foam Au driven by 4ω–2ω ignition laser pulse for inertial confinement fusion

Lan

Song

2017

Physics of Plasmas

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Green light (2ω) has the potential to drive ignition target for laser fusion with significantly more energy than blue light (3ω) and a relatively higher damage threshold for the optic components in the final optic assembly, but it has issues of a relatively low laser to x-ray conversion efficiency and a hard x-ray spectrum as compared to 3ω. In this paper, we propose to drive a foam hohlraum wall with an ignition laser pulse by taking a 4ω laser at the pre-pulse and a 2ω laser at the main-pulse, called as 4ω -2ω ignition pulse. This novel design has the following advantages: (1) benefiting from 2ω of its relatively high energy output and low damage threshold during main-pulse; (2) benefiting from foam in its relatively high laser to x-ray conversion efficiency and relatively low M-band fraction in re-emission; (3) benefiting from 4ω of its low LPI during pre-pulse. From our 1D simulations with Au material, the laser to x-ray conversion in a foam driven by 4ω -2ω pulse has an increase of 28% as compared to a solid target driven by 3ω with the same pulse shape. The relatively thin optical depth of foam is one of the main reasons for the increase of laser to x-ray conversion efficiency inside a foam target.

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“…Two laser facilities are built to achieve ICF with indirect drive configuration: the National Ignition Facility (NIF) in U.S.A. [3] and the Laser MégaJoule (LMJ) in France [4]. For LMJ, directly-driven self-ignition is possible [1] with indirect-drive beam geometry with zooming [5].…”

Section: Introductionmentioning

confidence: 99%

“…In this scheme, compression phase and ignition are separated. Usually, targets designs present high initial aspect ratio A, defined as the ratio of the deuterium-tritium (DT) ice-layer inner radius over the DT-ice layer thickness, around A = 7 for Fast-Ignition (FI) [9] or for Direct-Drive (DD) targets [1] and around A = 11 for indirect drive targets [4]. In our study, we explore low initial aspect ratios and moderate implosion velocities.…”

Section: Introductionmentioning

confidence: 99%

Systematic analysis of direct-drive baseline designs for shock ignition with the Laser MégaJoule

Brandon

Canaud

Laffite

et al. 2013

EPJ Web of Conferences

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Abstract. We present direct-drive target design studies for the laser mégajoule using two distinct initial aspect ratios (A = 34 and A = 5). Laser pulse shapes are optimized by a random walk method and drive power variations are used to cover a wide variety of implosion velocities between 260 km/s and 365 km/s. For selected implosion velocities and for each initial aspect ratio, scaled-target families are built in order to find self-ignition threshold. High-gain shock ignition is also investigated in the context of Laser MégaJoule for marginally igniting targets below their own self-ignition threshold.

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Target design for ignition experiments on the laser Mégajoule facility

Cited by 31 publications

References 17 publications

Stochastic homogenization of the laser intensity to improve the irradiation uniformity of capsules directly driven by thousands laser beams

Stochastic homogenization of the laser intensity to improve the irradiation uniformity of capsules directly driven by thousands laser beams

Foam Au driven by 4ω–2ω ignition laser pulse for inertial confinement fusion

Systematic analysis of direct-drive baseline designs for shock ignition with the Laser MégaJoule

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