The influence of driven asymmetry on yield degradation in shaped-pulse indirect-drive implosion experiments at the 100 kJ laser facility

Yan, Jiwang; Shen, Hao; Chen, Zhong Jing; Cao, Haiqing; Sun, Chuan Kui; Dai, Zhen Sheng; Li, Ji Wei; Jiang, Wei; Song, Zi Feng; Peng, Xiao; Zou, Xing; Yu, Bo; Pu, Yu Dong; Huang, Tian Xuan; Dong, Yun Song; Wang, Lifeng; Jiang, Shaoen; Xie, He

doi:10.1088/1741-4326/abbf61

Cited by 4 publications

(3 citation statements)

References 69 publications

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“…The gas-filled capsules are imploded to confirm the drive symmetry. The shapes of hotspot self-emission images characterize the drive symmetry [33]. In current cryogenic layered implosion experiments, we not control time-dependent drive symmetry via time-varying cone fraction (CF).…”

Section: Resultsmentioning

confidence: 99%

Demonstration of indirectly driven implosion experiments with cryogenic pure deuterium layered capsules on the Shenguang Laser Facility

Wang

et al. 2023

Nucl. Fusion

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To achieve ignition in a laboratory via inertial confinement fusion, a spherical capsule containing a frozen layer of deuterium and tritium (DT) fuel will be imploded on an MJ-class laser facility. However, if pure deuterium fuel can be used in place of DT fuel for tuning shots, we may speed up the process of ignition experiments while maintaining the surrogacy by significantly reducing the level of radioactivity. Unfortunately, it has long been assumed that neither the approach of symmetrical infrared irradiation used in the Omega direct-drive experiments nor the method of beta-layering used in the NIF experiments can be used to smooth the D layered capsule in cylindrical hohlraums. The difficulty in smoothing the D ice layer prevents us from taking advantage of cryogenic D-layered capsules in indirect-drive experiments. In this work, we established a procedure to form a uniform D-ice layer for capsules held in cylindrical hohlraums and carried out indirect-drive cryogenic D-layered implosion experiments using a squared laser pulse on the Shenguang laser facility in China. The quality of the D ice layer is characterized by phase-contrast imaging. The root-mean-square of the power spectrum in modes 2-100 is about 2.2μm. The implosion performance of the D-layered capsules is close to the prediction of one-dimensional simulations. The measured neutron yield and areal fuel density are 1.2×1011 and 80mg/cm2, respectively.

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Section: Resultsmentioning

confidence: 99%

Demonstration of indirectly driven implosion experiments with cryogenic pure deuterium layered capsules on the Shenguang Laser Facility

Wang

et al. 2023

Nucl. Fusion

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“…近年来, 在我国100 kJ激光装置上, 基于直柱黑腔开展的两台阶整形脉冲驱动内爆实验研究已经取得较大进展 [7,8] . 为了进一步提高内爆性能, 物理设计要求使用三台阶整形脉冲驱动开展内爆物理实验研究.…”

Section: 内爆实验设计与方法unclassified

Improving symmetry tuning with I-raum in indirect-driven implosions

Huang¹,

Wu²,

Chen³

et al. 2023

Acta Phys. Sin.

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Indirectly driven inertial confinement fusion implosions using a three-step- shaped pulse were performed at the 100kJ laser facility. At late time of the pulse, deposition of laser energy and distribution of x-ray radiation were significantly disturbed by motion of gold plasma in the original gas-filled cylindrical hohlraum with gold wall. As a result, the lack of x-ray drive at the equator of the capsule generated an unacceptable oblate implosion. In the I-raum modified from the above cylindrical hohlraum, the initial positions of outer laser spots and gold bubbles were properly shifted to modify the disturbed radiation distribution, due to plasma evolution, resulting in a spherically symmetric drive on the capsule. In implosion shots with almost the same drive pulse, owing to improved symmetry, an spherical hotspot was observed in the new I-raum, and YOS (measured neutron yield over simulated one dimensionally ) was up to 30%, while an oblate hotspot was observed in the cylinder, and YOS was 13%. Both simulation calculations and experimental measurements show that, the I-raum can be used to significantly reduce the impact of gold bubble expansion in the three-step-shaped pulse driven implosion, which helps to tune the drive and implosion symmetry, and to improve its over-all performance.

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“…Over the past few decades, the ICF community has performed a lot of experiments to measure implosion asymmetries and explore the impact of low-mode drive asymmetries on the implosion performances [11][12][13][14][15][16][17][18][19]. Meanwhile, significant efforts have been dedicated to theoretical investigations on the sensitivity of the implosion performances to low-mode drive asymmetries.…”

Section: Introductionmentioning

confidence: 99%

A 2D dynamic model for the impact of time-dependent low-mode drive asymmetries on the shell asymmetries during acceleration phases of ICF implosions

Li¹,

Gu²,

Kang³

et al. 2023

Plasma Phys. Control. Fusion

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Low-mode drive asymmetries are known as signiﬁcant performance degradation factors in indirect-drive inertial conﬁnement fusion (ICF) implosions. We propose a two-dimensional (2D) dynamic model to explore the impact of time-dependent low-mode drive asymmetries on the shell asymmetries in acceleration phases of implosions. Since during acceleration, the shell areal density (ρRs) asymmetries are relatively small, we can treat the shell as thin shell pieces with ﬁnite mass and inﬁnitesimally small thicknesses, neglecting the angular ﬂows between these pieces. The radial motion of each shell piece is dominated by Newton’s law. Through this model, the evolution of the shell radial velocity vs and the shell radius Rs asymmetries of degree n can be characterized in terms of the drive temperature, time-dependent drive asymmetry of degree n and the average ρRs, vs, Rs obtained from one-dimensional (1D) simulations. The acceleration phases of typical gas-ﬁll capsule and layered DT capsule implosions with P2 or P4 drive asymmetries are explored using this model and validated using both 2D radiation hydrodynamic simulations and available backlit shell distortion measurements. This model gives a useful tool for ICF design, with an advantage of simplicity and speed.

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The influence of driven asymmetry on yield degradation in shaped-pulse indirect-drive implosion experiments at the 100 kJ laser facility

Cited by 4 publications

References 69 publications

Demonstration of indirectly driven implosion experiments with cryogenic pure deuterium layered capsules on the Shenguang Laser Facility

Demonstration of indirectly driven implosion experiments with cryogenic pure deuterium layered capsules on the Shenguang Laser Facility

Improving symmetry tuning with I-raum in indirect-driven implosions

A 2D dynamic model for the impact of time-dependent low-mode drive asymmetries on the shell asymmetries during acceleration phases of ICF implosions

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