真空中紫外辐射冲量与铝表面作用的模拟

SIMULATION OF UV RADIATION IMPULSECOUPLING TO ALUMINIUM SURFACE INVACUUM

为研究激光脉冲与真空中被照射的铝靶的耦合作用，进行了理论分析和数值计算，所给的结果是依据包括热传导、气化和等离子体燃烧在内的数学模型得到的。指出了对汽化过程的正确描述和重要性。同时发现双光子电离可导致初始电子数密度和其温度的增加。这一效应，从长远来看会导致激发态原子密度和电子产生速率的增加，但这是以降低光电离的产生为代价的。计算所得冲量耦合和等离子体阈值数据与实验结果吻合的较好。

Theoretical analysis and numerical calculations have been perfofrmed toinvestigate the laser impulse coupling to aluminium targets irradiated in vacuum. The re-sults presented are obtained on the basis of the mathcmatical model including heatconduction,vaponzation and plasma ignition. The significant role of a correct descrip-tion of the vaporization process is shown. It is found also that the two-photonionization results in increasing the initial electron number density and their temperature.This,in the long run, results in increasing the excited atoms number density, and therate of electron origination at the expense of their photoionization grows accordingly. Theimpulse coupling and plasma ignition threshold data are shown to be in good agreementwith experimental results.