激光聚变靶丸前中期温度演化与熵增特性定量表征技术研究

As one of the major approaches towards controllable fusion energy, laser controlled fusion has come to the final stage of high gain ignition. Fuel entropy determines the final compressible state of the capsule and is a key parameter for ignition. Besides consecutive shock waves, capsule preheat sources such as hard X rays, hot electrons and non-local ion transportation can contribute to adiabat or entropy increase. For prevailing studies, Fuel entropy is evaluated only by matching experimental and simulation results on consecutive shock velocities during shock tuning process, which is less sensitive to preheat effects and may therefore underestimate entropy increase. This original research is dedicated for temperature and comprehensive entropy sources, i.e., taking preheat into consideration, during early shock tuning campaigns. It is designed to develop a wide range temperature evaluation technology with high precision which can be adaptable to both preheat and shock wave heat. A multi-parametric characterization on fuel entropy shall be presented through temperature evolution combined with shock velocity history. This technology will provide critical and reliable evaluation on capsule performance at early shock tuning stage. The outcome of the research will expand and be of great value to material property studies under extreme conditions.

作为实现可控聚变能源的主流途径之一，激光聚变研究在国内外都进入到实现高增益点火的冲刺阶段。靶丸材料熵增特性决定靶丸最终的可压缩状态，是影响点火的关键物理参数之一。靶丸熵增源除了冲击波做功熵增外，还有诸如硬x射线、超热电子以及非局域离子传输等预热效应熵增。现阶段，理论上通过多冲击波调速设计控制冲击波熵增，实验上通过数值模拟测量到的冲击波速度历程间接评估熵增，该方法评估预热熵增的灵敏度较低，存在低估熵增的风险。本课题创新性的利用靶丸前中期温度诊断发展综合熵增表征技术，发展适用于预热及冲击波熵增的高精度宽区温度测量技术，再结合多冲击波速度历程测量技术建立靶丸材料熵增多参数表征分析能力，最终对靶丸整形脉冲前中期内爆性能分析提供关键可靠的熵增评估。本课题成果将进一步拓展对极端条件材料物性实验测量能力，在极端条件物性研究具有重要应用价值。

激光惯性约束聚变中，靶丸材料熵增特性决定靶丸最终的可压缩状态，是影响点火的关键物理参数之一。在目前的研究方法中，主要通过多冲击波调速设计控制冲击波熵增，实验上通过评估模拟与测量到的冲击波速度历程之间的差异间接评估熵增。本课题通过发展实验瞬态高温测温技术，对低温预热和高温测温技术进行有效结合，创新性的发展了针对靶丸前中期驱动阶段冲击波调控中的综合熵增表征技术，发展适用于预热及冲击波熵增的高精度宽区温度测量技术，再结合多冲击波速度历程测量技术建立靶丸材料熵增多参数表征分析能力，最终对靶丸整形脉冲前中期内爆性能分析提供关键可靠的熵增评估，为定量的熵增提供了更可靠的多参量评估方法。通过在大型激光装置上开展研究，初步验证了实验方法的有效性。本研究成果将进一步对优化聚变点火设计提供有益帮助，同时，进一步拓展对极端条件材料物性实验测量能力，在极端条件物性研究具有重要应用价值。