Competition among the two-plasmon decay (TPD) of backscattered light of stimulated Raman scattering (SRS), filamentation of the electron-plasma wave (EPW) and forward side SRS is investigated by two-dimensional particle-in-cell simulations. Our previous work [K. Q. Pan et al., Nucl. Fusion 58, 096035 (2018)] showed that in a plasma with the density near 1/10 of the critical density, the backscattered light would excite the TPD, which results in suppression of the backward SRS. However, this work further shows that when the laser intensity is so high ( $>{10}^{16}$ W/cm²) that the backward SRS cannot be totally suppressed, filamentation of the EPW and forward side SRS will be excited. Then the TPD of the backscattered light only occurs in the early stage and is suppressed in the latter stage. Electron distribution functions further show that trapped-particle-modulation instability should be responsible for filamentation of the EPW. This research can promote the understanding of hot-electron generation and SRS saturation in inertial confinement fusion experiments.

单晶金刚石是一种性能优异的晶体材料, 在先进科学领域具有重要的应用价值。在微波等离子体化学气相沉积(Microwave plasma chemical vapor deposition, MPCVD)单晶金刚石生长中, 如何提高晶体的生长速率一直是研究者们关注的重点问题之一, 而采用高能量密度的等离子体是提高单晶金刚石生长速率的有效手段。在本研究中, 首先通过磁流体动力学(Magnetohydrodynamic, MHD)模型仿真计算, 优化设计了特殊的等离子体聚集装置; 随后基于模拟结果进行生长实验, 采用光谱分析和等离子体成像对等离子体性状进行了研究, 制备了单晶金刚石生长样品; 并通过光学显微镜、拉曼光谱对生长样品进行测试。模拟结果显示, 聚集条件下的核心电场和电子密度是普通条件下的3倍; 生长实验结果显示, 在常规的微波功率(3500 W)、生长气压(18 kPa)下得到的高能量密度(793.7 W/cm³)的等离子体与模型计算结果吻合。高能量密度生长条件并不会对生长形貌产生较大影响, 但加入一定量氮气能够显著改变生长形貌, 并对晶体质量产生影响。采用这种方法, 成功制备了高速率(97.5 μm/h)单晶金刚石。不同于通过增大生长气压来获得高能量密度的途径, 本研究在常规的生长气压和微波功率下也可以生长高能量密度单晶金刚石。

介绍了以强激光驱动电容线圈靶的实验方法产生磁场的基本模型及其发展过程。对比了实验室中常用的三种磁场诊断方法，包含：B-dot、法拉第旋转以及质子背光，发现前两种方法在实验中仅可以获得距离靶较远处的有限个磁场值，通过结合模拟工具获得靶处的磁场值与测量点的值跨越几个数量级，容易产生误差；质子背光诊断可以在实验中获得全局磁场信息，能够较好地满足线圈靶磁场诊断的需求。由于线圈靶磁场强且可持续时间长，在时空分布上具有一定可控性，因此我们将其应用到了磁重联的研究中，并成功获得了重联出流等特征。另外线圈靶在带电粒子的约束和磁流体动力学研究等多方面也得到了应用。

Fusion energy research is delivering impressive new results emerging from different infrastructures and industrial devices evolving rapidly from ideas to proof-of-principle demonstration and aiming at the conceptual design of reactors for the production of electricity. A major milestone has recently been announced in laser fusion by the Lawrence Livermore National Laboratory and is giving new thrust to laser-fusion energy research worldwide. Here we discuss how these circumstances strongly suggest the need for a European intermediate-energy facility dedicated to the physics and technology of laser-fusion ignition, the physics of fusion materials and advanced technologies for high-repetition-rate, high-average-power broadband lasers. We believe that the participation of the broader scientific community and the increased engagement of industry, in partnership with research and academic institutions, make most timely the construction of this infrastructure of extreme scientific attractiveness.

Thanks to a rapid progress of high-power lasers since the birth of laser by T. H. Maiman in 1960, intense lasers have been developed mainly for studying the scientific feasibility of laser fusion. Inertial confinement fusion with an intense laser has attracted attention as a new future energy source after two oil crises in the 1970s and 1980s. From the beginning, the most challenging physics is known to be the hydrodynamic instability to realize the spherical implosion to achieve more than 1000 times the solid density. Many studies have been performed theoretically and experimentally on the hydrodynamic instability and resultant turbulent mixing of compressible fluids. During such activities in the laboratory, the explosion of supernova SN1987A was observed in the sky on 23 February 1987. The X-ray satellites have revealed that the hydrodynamic instability is a key issue to understand the physics of supernova explosion. After collaboration between laser plasma researchers and astrophysicists, the laboratory astrophysics with intense lasers was proposed and promoted around the end of the 1990s. The original subject was mainly related to hydrodynamic instabilities. However, after two decades of laboratory astrophysics research, we can now find a diversity of research topics. It has been demonstrated theoretically and experimentally that a variety of nonlinear physics of collisionless plasmas can be studied in laser ablation plasmas in the last decade. In the present paper, we shed light on the recent 10 topics studied intensively in laboratory experiments. A brief review is given by citing recent papers. Then, modeling cosmic-ray acceleration with lasers is reviewed in a following session as a special topic to be the future main topic in laboratory astrophysics research.

激光聚变有望一劳永逸地解决人类的能源问题，因而受到国际社会的普遍重视，一直是国际研究的前沿热点。目前实现激光惯性约束聚变所面临的最大科学障碍（属于内禀困难）是对内爆过程中高能量密度流体力学不稳定性引起的非线性流动的有效控制，对其研究涵盖高能量密度物理、等离子体物理、流体力学、计算科学、强冲击物理和高压原子物理等多个学科，同时还要具备大规模多物理多尺度多介质流动的数值模拟能力和高功率大型激光装置等研究条件。作为新兴研究课题，高能量密度非线性流动问题充满了各种新奇的现象亟待探索。此外，流体力学不稳定性及其引起的湍流混合，还是天体物理现象（如星系碰撞与合并、恒星演化、原始恒星的形成以及超新星爆炸）中的重要过程，涉及天体物理的一些核心研究内容。本文首先综述了高能量密度非线性流动研究的现状和进展，梳理了其中的挑战和机遇。然后介绍了传统中心点火激光聚变内爆过程发生的主要流体力学不稳定性，在大量分解和综合物理研究基础上，凝练出了目前制约美国国家点火装置（NIF）内爆性能的主要流体不稳定性问题。接下来，总结了国外激光聚变流体不稳定性实验物理的研究概况。最后，展示了内爆物理团队近些年在激光聚变内爆流体不稳定性基础性问题方面的主要研究进展。该团队一直从事激光聚变内爆非线性流动研究与控制，以及聚变靶物理研究与设计，注重理论探索和实验研究相结合，近年来在内爆重要流体力学不稳定性问题的解析理论、数值模拟和激光装置实验设计与数据分析等方面取得了一系列重要成果，有力地推动了该研究方向在国内的发展。

基于脉冲功率技术的箍缩装置能够在cm空间尺度和百ns时间尺度产生极端的高温、高压、高密度以及强辐射环境。中物院流体物理研究所在已建成的10 MA级的大型箍缩装置上开展多种负载构型的高能量密度物理实验研究。利用Z箍缩动态黑腔创造出了惯性约束聚变研究所需的高温辐射场；研究了金属箔套筒和固体套筒的内爆动力学特性；利用中低Z材料内爆获得了可观的K壳层线辐射并用于X射线热-力学效应实验研究；磁驱动准等熵加载和冲击加载为材料动态特性研究提供了新的实验能力；采用环形二极管和反射三极管技术的轫致辐射源获得了高剂量（率）的X射线和γ射线；利用磁驱动的径向金属箔模拟了天体物理中恒星射流的形成及其辐射的产生。此外，还介绍了利用反场构型磁化靶聚变装置开展的预加热磁化等离子体靶形成等实验结果。

为了改善高能流密度飞秒激光的烧蚀质量，使用法布里珀罗腔产生子脉冲间隔在1~3 500 ps内连续可调的飞秒激光脉冲序列，系统探究了单个飞秒高斯脉冲与不同脉冲间隔的脉冲序列在硅上烧蚀的孔型质量。实验结果显示，子脉冲间隔在50~100 ps范围内时，孔边缘的冠状重熔物大大减少，其厚度仅为单个飞秒高斯脉冲的40%，周围基底几乎没有粘连的粉尘或热损伤痕迹，孔型品质因子数值从单个飞秒脉冲的0.52提升至0.89。本文报道的飞秒激光脉冲序列，基于后续子脉冲与喷出物的二次烧蚀原理，子脉冲间隔在50~100 ps范围内时，后续子脉冲能够最大程度的雾化喷出物，从而减少冠状重熔物与高温粉尘污染损伤，烧蚀质量得到改善。