High-gain shock ignition of direct-drive ICF targets for the Laser Mégajoule

Canaud, B.; Temporal, M.

doi:10.1088/1367-2630/12/4/043037

Cited by 55 publications

(45 citation statements)

References 27 publications

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“…Nevertheless, it is worth to [97] p = -6.87 p = -6.6 notice a significant difference in kinetic energies between initial aspect ratios, especially for low implosion velocities where the kinetic energy for ignition at A = 5 is the twice of A = 3. This should have strong implication for shock ignition at low implosion velocities [38]. Power law dependences with velocity are found the same whatever the definition of the energy (threshold or minimum for ignition) but with different exponents between A.…”

Section: Kinetic Energy Thresholdsmentioning

confidence: 73%

“…As already shown [38,39], when the design is far from its self-ignition kinetic energy, the spike power needed for ignition becomes well above 200 TW and thus intensities on target can trigger parametric instabilities [52,53], generates hot-electrons for which the transport can become a key issue for SI [39,52,54] and laser absorption could be reduced. For marginally igniting target, below and close to the self-ignition threshold, ignitor spike powers are reduced [38] and intensities can be close to parametric instabilities thresholds [51]. Such trade-off between reduced implosion velocity and ignition requirement leads us to design new targets that could meet both requirements and offer the opportunity to achieve tunable thermonuclear moderate gain on LMJ, as predicted for noncryogenic double-shell designs [55].…”

Section: Introductionmentioning

confidence: 94%

“…Such aspect leads also to strong requirement for the optimization of PDD with LMJ [50]. It has been shown also that the choice of a target design is crucial for the ignitor spike [38]. For instance, for the LMJ, a HiPER-like target design was used to address shock ignition feasibility and characteristics but the low laser-target coupling efficiency due to all-DT ablator appeared to be inefficient for direct-drive fusion on LMJ.…”

Section: Introductionmentioning

confidence: 99%

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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: Kinetic Energy Thresholdsmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

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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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“…For LMJ, directly-driven self-ignition is possible [1] with indirect-drive beam geometry with zooming [5]. Moreover, Shock Ignition (SI) [6] and its application on LMJ [7] bring a new interest for direct-drive approach because it can offer high gain for non selfigniting target and allows to investigate the self-ignition threshold [8]. In this scheme, compression phase and ignition are separated.…”

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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“…This very promising solution was recently proposed to ignite the Fast Ignition capsule of HiPER [12,13]. We address here the possibility of using this approach for LMJ with HiPER-like targets by a 1D-and 2D-analysis [14,15], considering the LMJ beam layout. Direct-drive shock-ignition of double shell targets [16] is also adressed.…”

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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High-gain shock ignition of direct-drive ICF targets for the Laser Mégajoule

Cited by 55 publications

References 27 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

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

Direct-drive shock-ignition for the Laser MégaJoule

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