氮化铀涂层贫铀黑腔抑制受激布利渊散射实验研究

In indirect-drive inertial confinement fusion, stimulated brillouin scattering (SBS) is generated in the hohlraum through laser plasma interactions. SBS is disadvantageous to the ignition owing to the negative effects on laser energy efficiency and driven symmetry. We plan to carry out an experimental research on SBS applying the uranium hohlraum with a uranium nitride coating layer. Adding the low-Z nitrogen element in the major high-Z material can theoretically increase Laudau damping rate of the plasma ion acoustic wave, which is inversely proportional to the gain rate of SBS. Based on the program, we envision that a novel design of the coated uranium hohlraum with new parameters including the coating thickness and atomic ratio could be obtained, which can significantly depress SBS.

在激光间接驱动的惯性约束聚变中，激光与黑腔等离子体相互作用产生的受激布利渊散射（SBS），会降低激光能量利用效率和辐射场对称性，从而对靶丸燃料的压缩点火造成不利影响。因此抑制黑腔SBS具有十分重要的意义。本项目拟对氮化铀涂层的贫铀黑腔开展研究，探索氮化铀厚度和铀氮原子比等参数对离子声波朗道阻尼率及SBS增益因子的作用机制，并通过设计和制备合适参数的氮化铀涂层来显著降低黑腔SBS份额。由于氮化铀涂层铀腔已被前期实验证实在提高激光X光转换效率和优化M带X光能谱方面比传统金腔更有优势，如能同时降低SBS份额，该新型腔壁材料所获得的黑腔综合性能将比现有其它方案更好。