利用成像型速度干涉仪进行聚苯乙烯材料中冲击波调速的实验研究

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

利用一维实验,模拟了惯性约束聚变中烧蚀层中冲击波传输和多次冲击追赶过程.针对聚苯乙烯材料(CH)容易被X射线离化的问题,通过较详细的数值模拟,分析了用Au和Cu做阻挡层对冲击波信号的影响.利用两种不同的辐射源,研究了辐射源两个台阶强度变化对两次冲击信号的影响.经过分析,使用在Al基底上面加厚度为5μm的Au膜以挡X射线的办法,获得了单次冲击在CH材料中加载和减速的清晰条纹图.利用在Al基底上加厚度为2μm的Au膜和厚度为3μm的Cu膜的方法,获得了两次冲击在CH材料中加速、减速和二次加载的条纹图.实验证明,适当加大辐射源两个台阶强度的差别,选用阻抗较低的Cu和阻抗较高的Au配合做阻挡材料会获得更好的双冲击结果.这些实验结果为进一步开展辐射驱动条件下CH材料中的冲击波传输过程提供了很好的基础数据.

The shock timing experiment in ablator material wave,where the shock wave transferring and catching up are investigated,can be simulated with an inertial confinement fusion planar target.The photo ionization effect caused by the X-ray from Hohlraum target is explained.With the simulation data,the block effects of Au and Cu for shock wave are analyzed.The shock velocity and the transfer time of two-shock wave in CH material are compared by using two radiation sources.The shock signals of acceleration and deceleration are obtained after adding Au block layer with thickness 5μm to the Al layer.The shock signals of acceleration,deceleration and reloading for two shock wave experiment are achieved after adding Au layer with thickness 2μm and Cu layer with thickness 3μm.The experimental data show that the two conditions should be satisfied in order to obtain the two shock signals.The first condition is that the difference in radiation between two steps source should be large,and the second condition is that the shield layer should be the combination of high impedance Au and low impedance Cu.These experimental results show the shock timing ability of ＂Shenguang-Ⅲ＂,and give the reference design for planar target in shock timing technique.