利用高功率激光驱动冲击波进行金材料状态方程实验测量

利用“神光-Ⅱ”装置第九路输出的倍频激光,采用直接驱动方式进行了金(Au)材料状态方程(EOS)实验。首先采用透镜列阵均匀辐照技术对输出的倍频激光进行了光束匀滑,平面靶实验结果显示冲击波具有良好的平面性,间接表明靶面上驱动激光强度的空间分布比较均匀。同时采用多台阶靶技术,对驱动冲击波的传播稳定性进行了实验测量,结果表明冲击波在实验测试的靶厚度范围内都是稳定传播的,实验结果与数值模拟结果也符合得较好。在此基础上,采用阻抗匹配方法,实验测量了金材料的状态方程,在金材料中获得了高达2.7 TPa的冲击压强,冲击波速度测量相对扩展不确定度达2%(K=2),并将实验数据与已有实验数据及状态方程模型进行了比较。

Experimental Measurements on Equation of State of Gold by Using High Power Laser Driving Shocks

Equation of state (EOS) experiments were performed using a double-frequency (2ω) laser pulse, which exported from the ninth beam of “SG-Ⅱ” laser facility. The ninth laser beam was smoothed by lens-array (LA) uniform illumination technique to generate a flat-top intensity distribution at the target plane and planar shock fronts in targets, which was validated by the plane-target experiments. The shockwave stabilities were experimentally measured by the multi-step target technique. The results showed that the shocks were steady enough during the target thickness range in which the shock velocity was measured. Also, the results were consistent with the numerical simulation results. On this base, the Au EOS was measured by using the impedance-matching technique. Shock pressure higher than 2.7 TPa was achieved in Au, and the relative expanded uncertainties of the measured shockwave velocity were 2% (K=2). Moreover, the experimental data were compared with existing experimental data and EOS models.