【作者】 张继彦；

【导师】 杨向东；

【作者基本信息】 四川大学 ， 原子与分子物理， 2002， 博士

【摘要】 激光等离子体发射的X射线谱中包含着十分丰富的信息，是研究等离子体形成、发展并进行状态诊断的有力工具之一，在惯性约束聚变研究中具有非常重要的意义。本文对激光等离子体的KeV能区X光发射和吸收的原子物理机制、占据动力学、谱结构及其时间演化等方面进行了深入的理论和实验研究。 首先，研究了产生X光辐射的高剥离态离子的离子结构，提出了基于多组态Dirac-Fock模型和组态平均思想的相对论组态平均能的计算方法。在此基础上，对高Z元素高离化度离子的能级劈裂规律进行仔细分析，建立了计算高Z高剥离态离子相对论组态平均能的解析拟合公式。 其次，建立了稳态碰撞辐射平衡和局域热动平衡条件下的等离子体发射谱和吸收谱理论计算模型，分别对铝、氪和金元素激光等离子的发射光谱以及铝等离子体的吸收谱进行了理论模拟。并且，通过将上述光谱模型与一维辐射流体动力学模拟相结合，对Al激光等离子体的KeV能区发射谱的时间行为进行了理论模拟。 最后，对激光等离子体的KeV能区光谱的实验测量问题，如晶体衍射效率、谱仪几何结构因子以及胶片响应等进行了讨论；建立了时间分辨和空间分辨的高谱分辨光谱测量系统，分别对Al激光等离子体的时间分辨K壳层发射谱以及Au激光等离子体的空间分辨M带发射谱进行了实验测量，并应用实验测量光谱进行了电子温度和电子密度诊断研究。更多还原

【Abstract】 The X-ray spectra emitted from laser-produced plasmas contain plentiful information. It is a powerful tool to carry out plasma diagnosis and to study the formation and evolution of the plasmas as well. It plays a significant role in the field of inertial confinement fusion. In this paper, the atomic physics mechanism, emission , absorbing and the time-dependent evolution of the KeV X-ray spectra are studied in details both experimentally and theoretically.Firstly, the structures of the highly-striped ions that emit or absorb X-ray are investigated, and a method for calculating the relativistic configuration-averaged energies basing on the multiconfigurational Dirac-Fock model and configuration averaging is presented. According to this method, the regular changes of the energy splitting occurred in highly-charged ions are carefully studied, and analytically fitted formulas for calculating the subconfiguration-averaged energies of high Z elments are given.Secondly, a theoretical model for simulating the the emission and absorbing of X-ray are established basing on the stable collisional-radiative equilibrium and the local thermodynamical equilibrium model. Moreover, time-dependent characteristics of the X-ray spectra emitted from laser-produced Al plasma are modeled by coupling an one-dimensional radiative hydrodynamics code with this spectral model.Finally, some issues related to the experimental measurements of the KeV X-ray,such as the diffractional efficiency of crystal, the geometrical factor and the film response, are discussed. Furthermore, time-resolved and space-resolved high spectra resolution measurement systems are set up and used to measure the K-shell emission of the laser-produced Al plasma and the M-band emission of the laser-produced Au plasma respectively. Using the measured spectra, studies on the diagnosis of the electron density and electron temperature of the plasmas are also carried out.更多还原