氘氘冰层贯穿性缺陷对ICF冷冻靶内爆性能的影响

doi:10.19596/j.cnki.1001-246x.8429

摘要/Abstract

摘要：

使用二维多群辐射扩散流体力学程序LARED-S, 模拟研究DD冰贯穿性缺陷在方波驱动DD冷冻靶内爆过程中的演化行为及其对内爆性能的影响。模拟结果表明: DD冰层贯穿性缺陷显著降低DD冷冻靶内爆的中子产额, 二维模拟产额仅为一维结果的23.8%。DD冰层贯穿性缺陷使靶丸CH(Si)的烧蚀层生成大幅度的尖钉, 穿透到芯部热斑区。在中子bang-time时刻, 热斑区混入了487 ng的烧蚀物质, 使芯部韧致辐射漏失功率相对一维理想内爆显著升高, 离子温度与DD核反应速度相应降低。同时, 高密度的烧蚀层尖钉把DD热斑推离球心, 显示明显的P1不对称性, 而且高温热斑具有定向流动速度, 降低了内爆动能转化为热斑内能的效率。

关键词: 惯性约束聚变, 氘氘冰层, 贯穿性缺陷, P1不对称性

Abstract:

A two-dimensional radiation diffusion hydrodynamic code LARED-S is used to investigate evolution behavior of a penetrating defect and its influences on square-pulsed DD cryogenic capsule implosion performance. It shows that a penetrating defect on DD ice layer reduces significantly the neutron yield with a YOC of 23.8%. The defect makes the Si-doped CH ablator layer produce a high-amplitude inward-facing spike, penetrating into the central DD gas. A large amount of ablation material is mixed into the hot spot with a mixing mass of 487 ng, leading to a significant increase in the bremsstrahlung radiation loss power from the hot spot compared to the 1D ideal implosion result. It results in a large reduction in the hot-spot temperature and the final DD reaction rate. Meanwhile, the high-density shell spike pushes the hot spot away from the capsule center, exhibiting a great P1 asymmetry. The P1-asymmetric hot spot has an obvious bulk flow velocity, which reduces the conversion efficiency of implosion kinetic energy into the internal energy of the hot spot.

Key words: inertial confinement fusion, deuterium-deuterium ice layer, penetrating defect, P1 asymmetry

谷建法, 葛峰峻, 戴振生, 康洞国, 邹士阳. 氘氘冰层贯穿性缺陷对ICF冷冻靶内爆性能的影响[J]. 计算物理, 2022, 39(3): 268-276.

Jianfa GU, Fengjun GE, Zhensheng DAI, Dongguo KANG, Shiyang ZOU. Influence of Penetrating Defect in DD Ice Layer on ICF Cryogenic Capsule Implosion Performance[J]. Chinese Journal of Computational Physics, 2022, 39(3): 268-276.

图/表 10

图1 (a) 方波脉冲辐射温度源曲线；(b) 靶丸结构示意图

Fig.1 (a) Radiation temperature curve of a square-pulse implosion; (b) A schematic of the capsule configuration

图2 DD冰层缺陷初始结构(a) AL=15 μm；(b) AL= 27 μm

Fig.2 Initial defects on inner surface of the DD ice (a) AL=15 μm and (b) AL= 27 μm

图3 内爆加速飞行阶段t=1.8 ns靶丸二维密度分布(a) AL=15 μm；(b) AL= 27 μm

Fig.3 Two-dimensional density profiles at t=1.8 ns of the acceleration phase (a) AL=15 μm and (b) AL= 27 μm

图4 最大内爆速度时刻t=2.0ns靶丸二维密度分布(a) AL=15 μm；(b) AL=27 μm

Fig.4 2D density profiles at peak velocity (t=2.0 ns) for the case of (a) AL=15 μm and (b) AL=27 μm

图5 Bang-time时刻DD冰缺陷幅度AL=15 μm的二维模拟结果：(a) 密度；(b) 离子温度；DD冰贯穿性缺陷AL= 27 μm的二维模拟结果：(c) 密度；(d) 离子温度

Fig.5 (a) Density and (b) ion temperature profiles at bang-time for the case of AL=15 μm; (c) Density and (d) ion temperature profiles for the case of AL= 27 μm

图6 2-D模拟后处理得到的中子图像(a) AL=15 μm；(b) AL= 27 μm

Fig.6 Post-processing neutron images for the cases of (a) AL=15 μm and (b) AL= 27 μm

图7 (a) 热斑P1不对称性幅度与(b) 热斑温度随DD冰缺陷幅度的变化

Fig.7 (a) P1 asymmetry amplitude of the hot spot and (b) hot-spot temperature as functions of the amplitude of void on the inner DD interface

图8 (a) DD核反应速率时间曲线，其中黑线为理想一维内爆模拟结果，红线为AL=15 μm的二维模拟结果，蓝线为AL=27 μm贯穿性缺陷的二维模拟结果；(b) 二维内爆模拟产额与一维产额的比值随DD冰缺陷幅度的变化

Fig.8 (a) DD reaction rate as a function of time for the 1D ideal implosion (black curve) and 2D implosion simulation with AL=15 μm (red curve) and AL=27 μm (blue curve); (b) 2D yield over clean (YOC) as a function of the amplitude of void on the inner DD interface

图9 DD冷冻靶热斑区韧致辐射漏失功率时间曲线(黑线为理想一维内爆模拟结果，红线为AL=15 μm的二维模拟结果，蓝线为AL= 27 μm贯穿性缺陷的二维模拟结果。)

Fig.9 Loss power of the bremsstrahlung radiation from the hot spot as a function of time for the 1D implosion (black curve) and 2D simulation with AL=15 μm (red curve) and 27 μm (blue curve) for a void defect on the DD ice

图10 AL= 27 μmDD冰贯穿性缺陷对应的内爆bang-time时刻二维流场分布(黑线代表靶丸流场的流线。)

Fig.10 Density profiles at bang-time for the 2D case of AL= 27 μm (Black curves are fluid streamlines.)

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