中文摘要：

激光辐照靶产生的等离子体电子密度的诊断对于惯性约束聚变、等离子体物理、高能量密度物理等相关领域的研究具有重要意义，特别是中、高Z材料等离子体临界面附近的电子密度分布信息的测量.采用波长13.9 nm的类镍银软X射线激光作为探针，利用双频光栅剪切干涉技术尝试诊断了激光辐照金平面靶产生的等离子体的电子密度分布.实验获得了清晰的干涉条纹图像，通过对条纹的初步处理，测量到的最高密度达到了约1.4倍临界密度.通过与相关理论程序模拟结果对比，发现实验与模拟存在一定的偏差，为进一步优化模拟程序提供了有益的参考.通过实验，充分表明了软X射线激光双频光栅干涉技术在诊断中、高Z材料临界密度附近区域等离子体方面的实用性.

英文摘要：

The diagnoses of laser-produced plasma electron density have important significance for inertial confinement fusion, plasma physics, high energy density physics and other relevant fields, especially for measuring electron density distribution information of medium and high-Z material plasma near the critical density surface. With 13.9 nm Ni-like Ag X-ray laser serving as a probe, using double frequency grating shearing interference technique, the electron density distribution of plasma produced by laser irradiating a gold planar target is measured. Clear interference fringe image is obtained. Preliminary deduction of the fringe shows that the maximum density measured is about 1.4 times the critical density. It is found that there are some discrepancies between experimental results and simulation results, which provides a useful reference to the further optimization of the simulation program. The experimental results fully demonstrate that the soft X-ray double frequency grating shearing interference technique is practical to diagnose near-critical-density plasma of medium and high-Z materials, which will have a good application value.