Irradiation uniformity and zooming performances for a capsule directly driven by a 32×9 laser beams configuration

Temporal, M.; Canaud, B.; Garrec, B. J. Le

doi:10.1063/1.3309489

Cited by 26 publications

(18 citation statements)

References 38 publications

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“…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]. In this paper we analyze the illumination nonuniformity of a spherical capsule directly irradiated by a large number of láser beams affected by unavoidable beam imperfections.…”

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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“…In the LMJ facility, the laser beams are grouped in quads; thus the power imbalance benefits from a statistical factor which reduces it to σ PI = 5% (quad-to-quad). The illumination non-uniformity, evaluated taking into account these beam uncertainties, is usually measured as an average value (σ ) estimated over a large number of calculations [72][73][74][75][76][77] . In these calculations, each of the three parameters (laser power, laser pointing, and target position) varies randomly and follows a Gaussian distribution centred to their nominal values and characterized by the corresponding standard deviation σ PI , σ PE , or σ TP .…”

Section: Illumination Non-uniformitymentioning

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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“…Included in the design as a mandatory requirement is the use of a phase plate to both condition the focal spot and create the necessary stationary speckle pattern. This bundle design has many advantages when considering focal spot conditioning, optical zooming, and pulse shaping; it has been described in detail in [22][23][24] . Both NIF and LMJ have shown that in solid-state lasers, the bandwidth is large enough to withstand phase modulation as a necessary requirement for beam smoothing and stimulated Brilloouin scattering (SBS) suppression.…”

Section: Laser Design: Architecturementioning

confidence: 99%

Challenges of high power diode-pumped lasers for fusion energy

Garrec

2014

High Pow Laser Sci Eng

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This paper reviews the different challenges that are encountered in the delivery of high power lasers as drivers for fusion energy. We will focus on diode-pumped solid-state lasers and we will highlight some of the main recent achievements when using ytterbium, cryogenic cooling and ceramic gain media. Apart from some existing fusion facilities and some military applications of diode-pumped solid-state lasers, we will show that diode-pumped solid-state lasers are scalable to inertial fusion energy (IFE)'s facility level and that the all-fiber laser scheme is very promising.

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Irradiation uniformity and zooming performances for a capsule directly driven by a 32×9 laser beams configuration

Cited by 26 publications

References 38 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

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

Challenges of high power diode-pumped lasers for fusion energy

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