利用神光Ⅱ装置上搭建的用于激光冲击波实验的温度诊断系统(该系统包括高时空分辨的扫描高温计和谱时分辨的扫描高温计)，以强激光加载铝材料冲击温度的测量，获得了铝材料冲击高温辐射发光谱的高时空分辨信号图像，结合灰体辐射理论模型，计算得到了冲击波速度19.06 km/s时铝材料的冲击温度达2.95 eV，该温度与SESAME库中冲击温度接近。研究结果表明采用该测温系统能够有效诊断金属材料的冲击温度，为后续进一步获取金属材料冲击温度数据奠定了基础。

High precision polystyrene equation of state data were measured using laser-driven shock waves with pressures from 180 GPa to 700 GPa. α quartz was used as standard material, the shock wave trajectory in quartz and polystyrene was measured using the Velocity Interferometer for Any Reflector (VISAR). Instantaneous shock velocity in quartz and polystyrene was obtained when the shock wave pass the interface. This provided ～1% precision in shock velocity measurements.

High-power laser induced shocks were used to study spall fracture of polycrystalline aluminum at strain rates more than 106/s at “Shenguang-Ⅱ” laser facility.The free surface velocity histories of shock-loaded samples,150 μm thick and with initial temperature from 293 K to 873 K,were recorded using velocity interferometer system for any reflector(VISAR).From the free surface velocity profile ,spall strength and yield stress are calculated,which shows that spall strength declines while yield strength increases with initial temperature increasing.The loaded samples were recovered for metallographic analysis through Laser Scanning Confocal Microscopy.It is found that there are more micro-voids and more bigger voids near the spall plane.Meanwhile,the grain size increases with temperature slowly except the sharp change at 893K(near melting point).Besides,the fracture mechanisms change from mainly intergranular fracture to transgranular fracture with initial temperature increasing.

在神光-Ⅱ装置上利用强激光加载铝材料进行高应变率(高于106s-1)层裂实验,研究不同初始温度下高纯铝材料的动态损伤特性.采用任意反射面速度干涉仪测量样品自由面速度剖面,由自由面速度剖面计算纯铝样品层裂强度与屈服应力.结果表明:随着温度升高,材料层裂强度减小,屈服应力增大.对激光加载前后样品进行金相分析,观察不同初始温度下纯铝材料的微介观结构变化及其损伤特性.结果表明:随着温度升高,样品晶粒尺度缓慢增大,但在873 K(近熔点)时晶粒尺度急剧增加;层裂面附近小孔洞数目较多,孔洞尺寸也较大,而远离层裂面处,孔洞数目相对较少,且尺寸也较小;材料的断裂方式随温度升高由沿晶断裂为主逐渐变为穿晶断裂为主.

In this paper, we systematically study preheating in laser-direct-drive shocks by using a velocity interferometer system for any reflector (VISAR). Using the VISAR, we measured free surface velocity histories of Al samples over time, 10–70 lm thick, driven directly by a laser at different frequencies (2x, 3x). Analyzing our experimental results, we concluded that the dominant preheating source was X-ray radiation. We also discussed how preheating affected the material initial density and the measurement of Hugoniot data for high-Z materials (such as Au) using impedance matching. To reduce preheating, we proposed and tested three kinds of targets.

在神光Ⅱ激光装置上，针对外径260 μm的柱形靶，采用大焦斑拼接的办法（焦斑直径约200 μm），开展了八路激光直接驱动压缩实验。利用第九路激光驱动钼X射线背光，使用KirkpatrickBaez显微镜成像以及条纹相机记录的方法，获得了柱形靶内爆流线图，据此给出的压缩后密度约为初始密度的120倍。该密度处于快点火电子产生区和能量沉积区密度之间，正是电子束需要传输的密度区域。神光Ⅱ皮秒激光运行后，可以利用这种压缩的柱形靶开展电子束在稠密等离子体中传输的实验研究。

A line-imaging optically recording velocity interferometer system (L-ORVIS) fitting the high-strain rate motion of solids as in shock wave experiments requires a high power single-mode laser. We have put forward a new illumination method which can increase threefold the luminosity of such a diagnostic. A modified illumination system is applied to the L-ORVIS which was implemented at ‘Shenguang-II’ laser facility. The modified L-ORVIS is applied to laser-driven shock wave experiments and platinum Hugoniots were obtained at both high pressure and low pressure.

Direct-drive and indirect-drive inertial confinement fusion (ICF) targets use temporally shaped drive pulses to optimize target performance. The timing of multiple shock waves is crucial to the performance of ICF ignition targets. Velocity interferometer system for any reflector (VISAR) is the principal diagnostic tool for shock-timing experiments. We present velocity measurements from the shock waves in polystyrene targets driven by two 200-ps pulses separated by 1–2 ns. These pulses drive two shock waves that coalescence in the target. Coalescence time and transit times are observed by VISAR.

Direct-drive and indirect-drive inertial confinement fusion (ICF) targets use temporally shaped drive pulses to optimize target performance. The timing of multiple shock waves is crucial to the performance of ICF ignition targets. Velocity interferometer system for any reflector (VISAR) is the principal diagnostic tool for shock-timing experiments. We present velocity measurements from the shock waves in polystyrene targets driven by two 200-ps pulses separated by 1–2 ns. These pulses drive two shock waves that coalescence in the target. Coalescence time and transit times are observed by VISAR.