精准的航迹跟踪是无人机实现任务规划的必要条件。针对自适应优化制导律(AOGL)算法中, 权重矩阵依靠先验知识或者试探选取、缺乏理论指导且未必最优的问题, 提出了一种基于粒子群优化AOGL航迹跟踪方法。将权重矩阵中各元素经验值乘以待优化系数, 代入黎卡提方程, 推导出修正之后的制导律, 进而构造目标函数进行寻优求解。在不同的扰动风速条件下, 针对线性、圆形期望跟踪航迹分别进行数值仿真, 结果表明, PSO-AOGL航迹跟踪效果更优, 可有效降低跟踪位置误差。

为了提高SLM成形Al-12Si合金的综合性能，通过气雾处理方式加入Er、Zr元素后进行SLM制备Al-12Si-(Er-Zr)合金。通过试验测试手段研究其微观结构、物理力学特性等指标，深入分析Er与Zr元素在Al-12Si-(Er-Zr)合金SLM加工过程中的强化作用机制。研究结果表明：在能量密度达到57.5 J/mm3时，合金获得99.2%的最高相对密度。SLM制备Al-12Si-(Er-Zr)合金中存在灰色Al与白色共晶Si组织，呈网状分布形态特征，Er、Zr元素可以对Al-12Si-(Er-Zr)合金起到明显晶粒细化的效果。与Al-12Si合金相比，SLM制备Al-12Si-(Er-Zr)合金硬度增大了26.1%，合金拉伸强度增大20%，屈服强度增大27%，伸长率变化不明显。SLM制备Al-12Si-(Er-Zr)合金晶粒都达到较大的Schmid因子，含有更多的高Taylor因子，更高比例Brass冷轧织构和Copper拉伸织构，使Al-12Si-(Er-Zr)合金获得更高的力学强度。

The articles in the “Atomic and molecular physics for controlled fusion and astrophysics” special issue cover a wide range of topics in atomic and molecular physics in the context of hot plasmas. Basic atomic processes are of fundamental importance in confinement fusion and astrophysical environments, and also for ultrahigh–intensity interaction of lasers with matter. Atomic physics in extreme environments such as high pressures and hot or dense plasmas^1,2 presents new challenges to the community, and these have to be addressed by both theoretical and experimental studies. Several extreme configurations are investigated in this special issue, which should be understood as an initiative to draw the attention of the community to important ongoing work in the context of extreme states of matter. This special issue presents eight articles from scientists actively working in this field and shows the important advances that have been made in basic atomic processes and related areas of plasma properties and plasma diagnosis over the last few years.

时域间断元方法是近年来电磁场计算领域的重要进展之一。将基函数的插值点和数值积分点重合的质量集中技术是降低该间断元方法质量矩阵存储开销和提高计算效率的重要手段。通过谐振腔、带通滤波器以及光子晶体内的电磁场等数值算例, 在四边形网格上比较了传统的质量集中算法和近来提出的 Weight-Adjust 算法之间的差异。计算结果表明, 尽管两种方法的存储量一样, 但Weight-Adjust 算法具有更高的精度。

Dense Z-pinch plasmas are powerful and energy-efficient laboratory sources of X-rays, and show the possibility to drive inertial confinement fusion (ICF). Recent advances in wire-array Z-pinch and Z-pinch dynamic hohlraum (ZPDH) researches at the Institute of Applied Physics and Computational Mathematics are presented in this paper. Models are setup to study different physical processes. A full circuit model (FCM) was used to study the coupling between Z-pinch implosion and generator discharge. A mass injection model with azimuthal modulation was setup to simulate the wire-array plasma initiation, and the two-dimensional MHD code MARED was developed to investigate the Z-pinch implosion, MRT instability, stagnation and radiation. Implosions of nested and quasi-spherical wire arrays were also investigated theoretically and numerically. Key processes of ZPDH, such as the arrayefoam interaction, formation of the hohlraum radiation, as well as the following capsule ablation and implosion, were analyzed with different radiation magneto-hydrodynamics (RMHD) codes. An integrated 2D RMHD simulation of dynamic hohlraum driven capsule implosion provides us the physical insights of wire-array plasma acceleration, shock generation and propagation, hohlraum formation, radiation ablation, and fuel compression.

Self-consistent calculations of energy loss for a Ga ion moving in hot Au plasmas are made under the assumption of wide ranges of the projectile energy and the plasma temperature with all important mechanisms considered in detail. The relevant results are found to be quite different from those of an a particle or a proton. One important reason for this is the rapid increasing of the charge state of a Ga ion at plasma temperature. This reason also leads to the inelastic stopping which does not always decrease with the increase of plasma temperature, unlike the case of an a particle. The nuclear stopping becomes very important at high enough plasma temperature due to the heavy reduced mass of a Ga and an Au ion and the above-mentioned reason. The well-known binary collision model [Phys. Rev. 126 (1962) 1] and its revised one [Phys. Rev. A 29 (1984) 2145] are not working or unsatisfactory in this case.

A sharp density increase (referred to as density incrustation) of the Au plasmas in the radiative cooling process of high-Z Au plasmas confined by low-Z CH plasmas is found through the radiative hydrodynamic simulations. The temperature of Au plasmas changes obviously in the cooling layer while the pressure remains constant. Consequently, the Au plasmas in the cooling layer are compressed, and the density incrustation is formed. It is also shown that when the high-Z plasma opacity decreases or the low-Z plasma opacity increases, the peak density of the density incrustation becomes lower and the thickness of the density incrustation becomes wider. This phenomenon is crucial to the RayleigheTaylor instability at the interface of high-Z and low-Z plasmas, since the density variation of Au plasmas has a considerable influence on the Atwood number of the interface.

Hot, dense plasmas exhibit screened Coulomb interactions, resulting from the collective effects of correlated many-particle interactions. In the lowest particle correlation order (pair-wise correlations), the interaction between charged plasma particles reduces to the DebyeeHu¨ckel (Yukawa-type) potential, characterized by the Debye screening length. Due to the importance of Coulomb interaction screening in dense laboratory and astrophysical plasmas, hundreds of theoretical investigations have been carried out in the past few decades on the plasma screening effects on the electronic structure of atoms and their collision processes employing the DebyeeHu¨ckel screening model. The present article aims at providing a comprehensive review of the recent studies in atomic physics in Debye plasmas. Specifically, the work on atomic electronic structure, photon excitation and ionization, electron/positron impact excitation and ionization, and excitation, ionization and charge transfer of ion-atom/ion collisions will be reviewed.