Implosion experiment of neutron yield in indirect driven double-metal-shell target
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摘要: 本文介绍了基于百千焦激光装置开展的一系列激光间接驱动双金属壳靶内爆出中子实验。双金属壳靶的设计来源于体点火方案,该方案通过解耦辐射烧蚀与内爆压缩过程,从而提高了内爆的鲁棒性。然而,由于双金属壳靶制备难度较大,首次实验中的中子产额远低于模拟预期。为解决这一问题,本文提出了两项关键改进措施:一是优化外壳接缝设计,降低流体力学不稳定性因素的影响,提高内外壳的碰撞效率以及内球的内爆效率;二是提高黑腔靶丸的耦合效率,增强激光能量的有效传递。通过这些改进,靶丸的压缩性能和内爆效率得到显著提升,最终实现了中子产额从
$ 5.0\times {10}^{7} $ 提升至$ 7.1\times {10}^{8} $ 。Abstract: This paper will discuss early experiments on laser-driven indirect drive implosion of double-metal-shell targets conducted with a hundred-kilojoule-class laser facility. The design of the double-metal-shell target is derived from the volume ignition scheme, which decouples the radiation ablation and implosion compression processes, thereby improving the robustness of the implosion. However, due to the high difficulty in manufacturing the double-metal-shell target, the neutron yield in the initial experiments was much lower than expected from simulations. To address this issue, two key improvements are proposed: first, optimizing the joint design of the outer shell to reduce the impact of hydrodynamic instability, thus improving the collision efficiency of the inner and outer shells and the implosion efficiency of the inner core; second, enhancing the coupling efficiency of the hohlraum-target to improve the effective transfer of laser energy. With these improvements, the compression performance and implosion efficiency of the target were significantly enhanced, resulting in a substantial increase in neutron yield, from$ 5.0\times {10}^{7} $ to$ 7.1\times {10}^{8} $ .-
Key words:
- volume ignition /
- double shell target /
- metal shell /
- joint /
- neutron yield
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表 1 不同发次的黑腔参数和辐射温度
Table 1. Hohlraum Parameters and Radiation Temperatures for Different Shots
Shot length of
hohlraum/μmdiameter of
hohlraum/μmdiameter of
LEH/μmhohlraum wall
materiallaser
duration/nssquare wave peak
power/TWlaser
energy/kJMeasurement
Tr_42/eV20182 5100 3000 1700 Au 3.0 1.0 147.1 238.2 21173 5100 3000 1700 Au 3.0 1.1 152.3 244.8 22019 4680 2600 1500 U 3.0 1.1 158.2 255.1 -
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