“三明治”靶型在间接驱动冲击波实验中的应用

Shock experiment with sandwiched target in laser indirect-drive experiment

间接驱动方式具有提供更高冲击波压力的潜力,对冲击波物理研究来说是一种很好的驱动方式.针对间接驱动下X射线离化对透明窗口造成的致盲问题,提出了新的"三明治"靶型结构,以完成间接驱动下冲击波实验.该靶型可以用两种方法避免致盲效应对实验的干扰.一种方法是从时间上避开致盲效应,使致盲效应与冲击波测量区错开,从而获得冲击波数据.另一种方法是从强度上屏蔽X射线,将X射线阻挡在透明材料之前,使其不能产生致盲效应.对单冲击实验而言,用增加烧蚀层厚度的方法,将X射线离化效应与冲击波信号从时间上错开,获得了蓝宝石和石英晶体中冲击波实验的结果.用增加阻挡层的方法,获得了间接驱动条件下石英晶体和聚苯乙烯材料中的冲击波实验结果.提出的"三明治"靶型,为间接驱动条件下状态方程和冲击波调速技术提供了技术支持.

Laser indirect-drive has the potential to get ultra-high pressure which is very useful for shock physics.The sandwiched target is used to suppress the ionization effect which causes the blanking area in optical streak camera （OSC） in indirect-drive experiment.The blanking effect can be avoided by the time scale and the intensity.With the thick ablator,the blanking effect appears before the shock wave arrives at the transparent material.Then the blanking effect can be avoided in time scale.With the high Z material,the X-ray which causes the blanking effect can be blocked before the transparent material.For one shock experiment,the shock wave result in Al2O3 is achieved after using the thick ablator to stagger the blanking effect and shock wave signal.The shock wave result in quartz and polystyrene material is obtained after the block layer has been added to the ablator layer.The sandwiched target provides the technique support for the equation of state and shock timing experiment in indirect-drive.