Progress in direct-drive fusion studies for the Laser 
Mégajoule

Canaud, B.; Fortin, X.; Garaude, F.; Meyer, C.; Philippe, F.

doi:10.1017/s0263034604222042

Cited by 41 publications

(22 citation statements)

References 4 publications

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“…This mass of DT fuel is expected to produce a fusion yield of order of magnitude of 30 MJ for a burn-up fraction of / ~ 30%. Such an initial aspect ratio is lower than baseline direct drive ones such as HiPER target [31] or direct-drive target for LMJ [58] or NIF [83] that are close to A = 7. Low initial aspect ratios have been chosen because, in principle, they are supposed to be more hydrodynamicaly stable during the implosion.…”

Section: Genesis Of Target Familiesmentioning

confidence: 96%

Low initial aspect-ratio direct-drive target designs for shock- or self-ignition in the context of the laser Megajoule

et al. 2014

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Analysis of low initial aspect ratio direct-drive target designs is carried out by varying the implosion velocity and the fuel mass. Starting from two different spherical targets with a given 300 /xg-DT mass, optimization of laser pulse and drive power allows to obtain a set of target seeds referenced by their peak implosion velocities and initial aspect ratio (A = 3 and A = 5). Self-ignition is achieved with higher implosion velocity for A = 5-design than for A = 3-design. Then, rescaling is done to extend the set of designs to a huge amount of mass, peak kinetic energies and peak areal densities. Self-ignition kinetic energy threshold Ek is characterized by a dependance of Ek ~ v& with ^S-values which depart from self-ignition models. Nevertheless, self-ignition energy is seen lower for smaller initial aspect ratio. An analysis of Two-Plasmons Decay threshold and Rayleigh-Taylor instability e-folding is carried out and it is shown that two-plasmon decay threshold is always overpassed for all designs. The hydrodynamic stability analysis is performed by embedded models to deal with linear and non-linear regime. It is found that the A = 5-designs are always at the limit of disruption of the shell.

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Section: Genesis Of Target Familiesmentioning

confidence: 96%

Low initial aspect-ratio direct-drive target designs for shock- or self-ignition in the context of the laser Megajoule

et al. 2014

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“…The purpose of the PDD is to adapt a non-optimal configuration of laser beams in order to optimize the uniformity of the capsule irradiation. To this purpose, in the PDD technique the laser beam directions are modified in order to optimize the direct drive capsule irradiation [48][49][50][51] . The use -as a direct driveof the quads in the second rings of the LMJ facility leads to an over-irradiation of the capsule polar regions, whilst the equatorial area is under-irradiated.…”

Section: The Laser Megajoule Configurationmentioning

confidence: 99%

Irradiation uniformity at the Laser MegaJoule facility in the context of the shock ignition scheme

Temporal

Canaud

Garbett

et al. 2014

High Pow Laser Sci Eng

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The use of the Laser MegaJoule facility within the shock ignition scheme has been considered. In the first part of the study, one-dimensional hydrodynamic calculations were performed for an inertial confinement fusion capsule in the context of the shock ignition scheme providing the energy gain and an estimation of the increase of the peak power due to the reduction of the photon penetration expected during the high-intensity spike pulse. In the second part, we considered a Laser MegaJoule configuration consisting of 176 laser beams that have been grouped providing two different irradiation schemes. In this configuration the maximum available energy and power are 1.3 MJ and 440 TW. Optimization of the laser-capsule parameters that minimize the irradiation non-uniformity during the first few ns of the foot pulse has been performed. The calculations take into account the specific elliptical laser intensity profile provided at the Laser MegaJoule and the expected beam uncertainties. A significant improvement of the illumination uniformity provided by the polar direct drive technique has been demonstrated. Three-dimensional hydrodynamic calculations have been performed in order to analyse the magnitude of the azimuthal component of the irradiation that is neglected in twodimensional hydrodynamic simulations.

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“…Direct drive inertial fusion on the laser Megajoule (LMJ) [1][2][3][4] is complementary to the indirect drive [5] to study inertial confinement fusion (ICF) and to produce high thermonuclear energy and gain. In direct drive, laser beams overlap on the external side of a spherical target and the irradiation uniformity has to be addressed carefully [6][7][8] in order to improve target hydrodynamic stability [9,10].…”

Section: Introductionmentioning

confidence: 99%

Direct-drive shock-ignition for the Laser MégaJoule

Canaud

Brandon

Laffite

et al. 2013

EPJ Web of Conferences

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Abstract. We present a review of direct-drive shock ignition studies done as an alternative for the Laser MégaJoule (LMJ). One and two dimensional systematic analyses of HiPER-like shock-ignited target designs are performed for the fuel assembly irradiation uniformity using the whole LMJ configuration or a part of the facility, and for the uniformity of the ignitor spike. High-gain shock-ignition is shown to be possible with intensity of each quad less than 10 15 W/cm 2 but low modes asymmetries displace the power required in the ignitor spike towards higher powers. Shock-ignition of Direct-Drive Double-Shell non-cryogenic targets is also addressed.

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Progress in direct-drive fusion studies for the Laser Mégajoule

Cited by 41 publications

References 4 publications

Low initial aspect-ratio direct-drive target designs for shock- or self-ignition in the context of the laser Megajoule

Low initial aspect-ratio direct-drive target designs for shock- or self-ignition in the context of the laser Megajoule

Irradiation uniformity at the Laser MegaJoule facility in the context of the shock ignition scheme

Direct-drive shock-ignition for the Laser MégaJoule

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