基于速度干涉仪的冲击波精密调速实验技术研究

冲击波精密调速技术是惯性约束聚变研究的关键技术之一. 针对冲击波精密调速诊断技术的要求, 以神光III原型上脉宽为3 ns的两台阶整形激光脉冲为源, 用石英晶体做窗口材料, 模拟了双冲击在石英晶体中传输和追赶的过程. 利用两发典型双冲击波调速的实验数据, 验证了神光III原型具有的精密调速能力. 实验结果表明, 在驱动源、 靶和诊断系统参数一致的条件下, 两发实验获得的实验结果中两次冲击出现的时刻, 冲击波速度都很一致. 通过精细分析, 发现在两次冲击交会的时刻, 干涉条纹清晰度和完整性变化最大, 最终数据处理获得的冲击波速度偏差也最大. 同时, 在二次冲击的冲击波速度有较大增加的条件下, 并没有观察到冲击波阵面的反射率的明显增加. 本文的实验结果作为一个数据依据, 为全面开展冲击波调速实验提供了有效的方法.

Shock timing experiment based on imaging velocity interferometer system for any reflector

The timing of multiple shock waves is crucial technique to the performance of inertial confinement fusion ignition targets. With the requirement for shock timing, the timing ability of Shen Guang-III prototype is analyzed by experimental data of two shots. The laser pulse in Shen Guang-III prototype is shaped in time scale, and the window material is z-cut quartz. The stream lines of two shock waves in quartz target are presented with Multi-1D program. Two steps of radiation drive two shock waves that coalesce in the quartz target, the resulting history, coalesce times, and transit times are observed in the stream lines. With the experiment results of two shots, the consistence of resulting history and coalesce times of two shock waves is provided under the same condition of laser pulse, target and diagnostic parameter. The differences in shock wave velocity, fringe contrast and quality occur at coalesce times of two shock waves. And the reflectivity of second shock wave does not increase compared with that of first shock wave. These experimental results and method provide the strong support for shock timing technique.