神光Ⅱ大型固体高功率激光装置是我国激光驱动器发展历史的里程碑, 其成功研制使我国高功率固体激光工程与技术、聚变物理与基础物理研究实现了全面且本质的跨越式发展。简要概述了神光Ⅱ激光装置研制中创新发展的大量工程方案与技术手段, 举例介绍了神光Ⅱ激光装置在近20年来的高质量运行中取得的众多有国际影响力的研究成果。经多方支持和多年持续发展, 已经形成数万焦耳级纳秒激光装置、皮秒拍瓦以及飞秒拍瓦激光装置等, 这些装置是我国惯性约束核聚变、强场物理、高能量密度物理等研究领域中重要的物理实验核心平台之一。

To probe the electron density distribution of the plasma,double-frequency grating shearing interferometry based on the soft X-ray laser technology is developed.The 13.9 nm Ni-like Ag soft X-ray laser is used as a probe to make attempt on the diagnosis of laser produced plasma from a planar gold wafer target.Clear interference fringes image is achieved,which fully demonstrates the practicability of this technology.However,there are some problems such as the unclear target surface in the image.Analysis indicates the main reasons of these problems and a reasonable solution is proposed to improve this technology.

针对高温稠密激光等离子体临界密度附近电子密度的诊断需求,发展了基于软X射线激光的软X射线双频光栅干涉诊断技术.利用波长13.9 nm的类镍银软X射线激光作为探针,掠入射式的双频光栅作为分光干涉元件,对激光辐照金平面靶产生的等离子体进行诊断尝试.实验获得了清晰的干涉条纹图像,充分表明该技术的实用性.但结果中存在靶面不清晰等问题,为此,提出了初步的解决方案.

结合快点火靶丸预压缩涉及的基本物理问题,分析了驱动激光脉冲波形对材料压缩过程的影响,并利用辐射流体力学程序MULTI模拟了不同激光波形下的材料压缩情况。结果表明:通过调节激光脉冲波形,优化激光初始强度、激光强度开始上升时间和上升速度,控制压缩过程中的熵增,可以获得更高的材料压缩度。

Experimental laboratory studies on the equation of state (EOS) based on laser driven shock waves has become a major way to obtain EOS data for materials above TPa pressures. Recent progress in laser EOS research is presented, with emphasis on the characteristics of laser driven shock waves, measurement methods in laser EOS experiments, research on shock wave planarity, stability and cleanliness, and the experimental results of such research.

The experiment of laser-driven Rayleigh-Taylor (RT) instability on Shenguang II (SG-II) facility has been presented. A Ni-like silver soft x-ray laser at 13.9nm has been used as a probe to take radiography of the modulation target RT instability first time. The modulation target is irradiated by a laser beam at 527nm of wavelength, 1500J of energy and 2.4ns of pulse width (FWHM), which is focused to intensity of 4×1014Wcm-2 on the target by a lens array. The evolvement of RT instability has been observed clearly. The results obtained by numerical simulation agree with that given by experiments.

It is important in fast ignition (FI) to drill a channel in the coronal plasma by a long intense pulse firstly, since we expect the following ultra-intense pulse will reach more easily the dense core to obtain the fuel burning. An experimental design to study the plasma channeling was presented at two beams laser sub-picosecond (SPS) Facility of National Laboratory of High Power Laser and Physics. One beam with 1.053 μm and 350 ps full width at half maximum (FWHM) was used to form the pre-plasma. And then, a most part of another one with the same wavelength and 1 ps FWHM was focused on the plasma for channeling. The rest part of the 1 ps laser beam, frequency quadrupled to λ=0.263 μm, was as a probe used in Normaski polarization interferometry to diagnosis the electron density distribution of the channel.

This paper presented the reults of experimental studies on transient soft X-ray laser using a picosecond pulsed laser facility. A rather intensity Ni-like Ag X-ray laser at 13.9 nm with output energy of about 5～10 nJ was obtained by irradiating the solid last targets with a several hundred picosecond long laser pulse in combination with an 1 ps ultra-short laser pulse.

The 30° Au conical targe tand Au foil target were irradiated by 20 TW ps P-polarized laser plasma, the characteristics of the forward produced hot electrons were studied. The hot electron number of the cone target was larget than that of the foil target, especially within the range of 2.0～2.5 MeV. The divergence of the forward hot electrons of the cone target was larger than that of the plane one, which was caused by different elecgron density of the pre-plasma with dissimilar target geometry produced by the driving laser.

Three sets of lens array (LA) uniform illumination system were designed, which were used in double-frequency laser direct drive experiments on "Shenguang-II" laser facility. Experimental investigations on shock planarity were carried out. The results show that the shock planarity has strong relationship with the LA's parameters, plane target's thickness and target's position. the shock planarity driven by the LA with 121 elements is the best, and which indirectly indicates that the illumination of the 121-element LA is the most uniform, too. Moreover, with the target thickness increasing, the shock planarity becomes worse, and the planar area becomes smaller. Also, the shock planarity showes some periodical change with the target's position, and the shock planarity at focal plane is the best for 121-element LA.