铝靶动态激光反射率的数值模拟

THE NUMERICAL SIMULATION OF REFLECTIVITYOF ALUMINUM ALLOY IRRADIATED BY LASER BEAM

从金属近自由电子模型——Ｄｒｕｄｅ／Ｆｒｅｓｎｅｌ理论出发，分析了激光作用下铝靶表面反射率的动态变化规律。通过对铝电导率与温度变化关系的数值模拟，得到了凝聚态、液态、气态反射率的动态变化规律，且与实验结果基本符合。当激光功率密度处于１０￣（１１）～１０￣（１５）Ｗ／ｃｍ￣２范围内时，由等离子体模型和局部热力学平衡（ＬＴＥ）理论，亦得到了反射率随温度变化的数值模拟结果，与国外的实验结果符合得较好。

Based on the free electron model-the Drude/Fresnel theory,the variation of re-flectivity of the aluminium surface under intense laser interaction is analysed in this paper. Fromthe numerical simulation of the relation of the aluminium conductivity with temperature,the in-stantaneous variations of the reflectivity at the aluminium surface in the solid ,liquid and vapourstates are conducted. The results are in accord with the experiments. When the laser power densityis in the range from 10￣(11)～10￣(16) W/cm￣2 ,the numerical simulation results of the reflectivity withtemperature are obtained according to the plasma model and the assumption of local thermal equi-librium(LTE). The results are approximate to the experimental results from abroad.