The modeling of non-local-thermodynamic-equilibrium plasmas is crucial for many aspects of high-energy-density physics. It often requires collisional-radiative models coupled with radiative-hydrodynamics simulations. Therefore, there is a strong need for fast and as accurate as possible calculations of the cross-sections and rates of the different collisional and radiative processes. We present an analytical approach for the computation of the electron-impact excitation (EIE) cross-sections in the Plane Wave Born (PWB) approximation. The formalism relies on the screened hydrogenic model. The EIE cross-section is expressed in terms of integrals, involving spherical Bessel functions, which can be calculated analytically. In order to remedy the fact that the PWB approximation is not correct at low energy (near threshold), we consider different correcting factors (Elwert-Sommerfeld, Cowan-Robb, Kilcrease-Brookes). We also investigate the role of plasma density effects such as Coulomb screening and quantum degeneracy on the EIE rate. This requires to integrate the collision strength multiplied by the Fermi-Dirac distribution and the Pauli blocking factor. We show that, using an analytical fit often used in collisional-radiative models, the EIE rate can be calculated accurately without any numerical integration, and compare our expression with a correction factor presented in a recent work.
Plasma screening and configuration interaction effects induced large enhancement on L-shell photoionization cross sections and opacity
National Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics（计算物理国家重点实验室，应用物理与计算数学研究所）；School of Optoelectronics, University of Chinese Academy of Sciences（中国科学院大学光电学院）；School of Mathematics and Physics, Qinghai University（青海大学理学院）；Center for Applied Physics and Technology, HEDPS, Peking University（北京大学高能量密度物理科学与技术研究院应用物理与技术中心）
该研究提出结合等离子体屏蔽和组态相互作用效应改进处理的不透明度模型，解释了铁、铬和镍不透明度相关差异，为太阳内部温度下 L 壳层不透明度测量提供系统解释，推动高能量密度等离子体中相关精确模拟。
Study of Coherent and Incoherent Plasma Emissions: Role of Plasma Wave Excitation and Breaking
在这里，我们实验映射的电子等离子体波在激光固体相互作用的动力学。我们做了时间分辨测量的二次谐波和硬X射线产生的相互作用的强（$10^{16} W cm^{-2}$，100 fs，800 nm）激光与固体表面上产生的预等离子体。在这个时间分辨研究中探索的参数空间包括尺度长度、激光偏振和激光强度的变化。这些测量一起完成带来了强驱动的电子等离子体波行为的新功能，这还没有被实验探索到目前为止。我们根据共振吸收和破波机制对结果进行建模。谐波和X射线发射显示出对比的行为，这表明试图通过蛮力来提高谐波效率的陷阱。然而，通过简单的调整，我们观察到，硬X射线可以增强或控制高达两个数量级和二次谐波高达一个数量级的最佳条件下。这些结果将有助于我们理解短波长产生和快速粒子产生的控制机制，以开发更有效的应用源。
A general expression for the excitation cross section of polarized atoms by polarized electrons
本文用原子极化理论的方法导出了极化电子对极化原子的激发截面的一般表达式。得到了描述极化和非极化原子激发态角分布和排列的一般表达式以及极化原子总激发截面的磁二色性的特殊情况。在扭曲波交换近似下，计算了Na的2 p $^5$ 3s $^2$ $^2$ P $_{3/2}$和K的3 p $^5$ 4s $^2$ $^2$ P $_{3/2}$的自电离激发截面和取向参数.
