大口径八边形钕玻璃片支撑系统的光机集成分析

控制由机械装夹方式所引入的波前畸变以提高惯性约束聚变(ICF)输出光束的质量，是在大口径钕玻璃片主放大器结构设计中必须考虑的。提出了一种新的有限元变形结果与光学元件面形畸变之间的数据处理方式，并与传统方式进行了对比。基于新的数据处理接口，利用光机集成分析方法对大口径八边形钕玻璃片的支撑系统结构设计参数进行优化。优化的结果保证了由支撑系统引起的透过波前畸变小于十分之一波长，同时波前畸变与设计参数变动的相关性最小。

一种ICF用新型可阵列反射镜架结构

运用并联机构原理设计了一种新型惯性约束聚变（Inetial Confinement Fusion, ICF）用可阵列反射镜架结构,并用坐标变换方法分析了机构的调整正交性与旋转轴正交性之间的关系.装置的实际测试结果表明调整正交性与分析结果一致,并且反射镜架的稳定性以及调节准确度均能符合ICF装置的使用要求.

高功率激光装置光束准直系统新型远场监测技术

利用高功率激光装置空间滤波器小孔成像和取样光栅的衍射,设计出一套新型光路远场监测方案,并且在实验平台上进行了实验验证.实验结果表明:相对传统的远场监测方法,该远场监测系统通过侧面离轴光栅取样灵活利用空间,其调整平均误差为空间滤波器小孔直径0.9%,能够满足准直系统远场调整精度(<小孔直径5%)的要求.

光谱色散后的相位调制光束衍射特性研究

用数值方法研究了激光驱动器系统中使用光谱色散平滑单元后光束的衍射特性、模拟结果表明，光谱色散会使光束衍射光斑变大，近场空间强度均匀性改善，而远场光斑内部存在光强接近于均匀分布的区域．进一步分析了光谱色散平滑单元中相位调制器的调制深度、调制频率及光栅色散系数等主要元件参数对光束传输特性的影响，发现在一定情况下光斑内部会出现较强的强度调制。

高功率双包层光纤放大器

高功率双包层光纤放大器在光纤传感、光纤通讯、光谱测量和惯性约束聚变等领域有广泛应用。介绍了两种获得放大激光输出的高功率双包层光纤放大器：单频双包层光纤放大器和脉冲双包层光纤放大器。分析了它们的工作原理及关键技术，并对国内外近期进展作了综述。

全电介质脉宽压缩光栅的研究进展

超短脉冲超高能量激光器作为研究光和物质相互作用以及惯性约束聚变的手段而得到了广泛的应用。综述了应用于啁啾脉冲放大(CPA)系统的脉冲压缩光栅(PCG)的发展概况；分析和评述了脉宽压缩光栅的设计原理和制作工艺，并给出了脉宽压缩光栅的发展展望。实践和理论证明采用多层膜介质衍射光栅是实现高性能脉宽压缩光栅的一种优良的设计方案。

光学薄膜元件的激光预处理技术

激光预处理技术作为一种提高激光约束核聚变装置中光学元件损伤阈值的有效方法，有重要的使用价值和学术价值。介绍了激光预处理的研究现状，重点介绍了小光斑光栅扫描预处理的方法及其应用，以及应注意的问题。讨论了几种被广泛认可的预处理增强机理，并对激光预处理技术进行了展望。

Relativistic Distorted-Wave Collision Strengths of Ni-, Cu- and Zn-like Au Ions

Excitation energies and electron impact excitation strengths from the ground states of Ni-, Cu- and Zn-like Au ions are calculated. The collision strengths are computed by a 213-levels expansion for the Ni- like Au ion, 405-levels expansion for the Cu-like Au ion and 229-levels expansion for the Zn-like Au ion. Configuration interactions are taken into account for all levels included. The target state wavefunctions are calculated by using the Grasp92 code. The continuum orbits are computed in the distorted-wave approximation, in which the direct and exchange potentials among all the electrons are included. Excellent agreement is found when the results are compared with previous calculations and recent measurements.

Proton Probing Measurement of Electric and Magnetic Fields Generated by ns and ps Laser-Matter Interactions

The use of laser-accelerated protons as a particle probe for the detection of electric fields in plasmas has led in recent years to a wealth of novel information regarding the ultrafast plasma dynamics following high intensity laser-matter interactions. The high spatial quality and short duration of these beams have been essential to this purpose. We will discuss some of the most recent results obtained with this diagnostic at the Rutherford Appleton Laboratory (UK) and at LULI - Ecole Polytechnique (France), also applied to conditions of interest to conventional Inertial Confinement Fusion. In particular, the technique has been used to measure electric fields responsible for proton acceleration from solid targets irradiated with ps pulses, magnetic fields formed by ns pulse irradiation of solid targets, and electric fields associated with the ponderomotive channelling of ps laser pulses in under-dense plasmas.

Measurement of Short-Range Correlations in Shock-Compressed Plastic by Short-Pulse X-Ray Scattering

We have performed short-pulse x-ray scattering measurements on laser-driven shock-compressed plastic samples in the warm dense matter regime, providing instantaneous snapshots of the system evolution. Time-resolved and angularly resolved scattered spectra sensitive to the correlation effects in the plasma show the appearance of short-range order within a few interionic separations. Comparison with radiation-hydrodynamic simulations indicates that the shocked plastic is compressed with a temperature of a few electron volts. These results are important for the understanding of the thermodynamic behavior of strongly correlated matter for conditions relevant to both laboratory astrophysics and inertial confinement fusion research.

Observation of the transient charging of a laser-irradiated solid

The proton radiography technique has been used to investigate the incidence of a 3 x10(19) W/cm(2) infrared pulse with a 125 mu m-diameter gold wire. The laser interaction is observed to drive the growth of a radial electric field similar to 10(10) V/m on the surface of the wire which rises and decays over a temporal window of 20 ps. Such studies of the ultrafast charging of a solid irradiated at high-intensity may be of relevance to schemes for laser-driven ion acceleration and the fast-ignitor concept for inertial confinement fusion.

Turning solid aluminium transparent by intense soft X-ray photoionization

Saturable absorption is a phenomenon readily seen in the optical and infrared wavelengths. It has never been observed in core-electron transitions owing to the short lifetime of the excited states involved and the high intensities of the soft X-rays needed. We report saturable absorption of an L-shell transition in aluminium using record intensities over 10(16)W cm(-2) at a photon energy of 92 eV. From a consideration of the relevant timescales, we infer that immediately after the X-rays have passed, the sample is in an exotic state where all of the aluminium atoms have an L-shell hole, and the valence band has approximately a 9 eV temperature, whereas the atoms are still on their crystallographic positions. Subsequently, Auger decay heats the material to the warm dense matter regime, at around 25 eV temperatures. The method is an ideal candidate to study homogeneous warm dense matter, highly relevant to planetary science, astrophysics and inertial confinement fusion.

Progress in proton radiography for diagnosis of ICF-relevant plasmas

Proton radiography using laser-driven sources has been developed as a diagnostic since the beginning of the decade, and applied successfully to a range of experimental situations. Multi-MeV protons driven from thin foils via the Target Normal Sheath Acceleration mechanism, offer, under optimal conditions, the possibility of probing laser-plasma interactions, and detecting electric and magnetic fields as well as plasma density gradients with similar to ps temporal resolution and similar to 5-10 mu m spatial resolution. In view of these advantages, the use of proton radiography as a diagnostic in experiments of relevance to Inertial Confinement Fusion is currently considered in the main fusion laboratories. This paper will discuss recent advances in the application of laser-driven radiography to experiments of relevance to Inertial Confinement Fusion. In particular we will discuss radiography of hohlraum and gasbag targets following the interaction of intense ns pulses. These experiments were carried out at the HELEN laser facility at AWE (UK), and proved the suitability of this diagnostic for studying, with unprecedented detail, laser-plasma interaction mechanisms of high relevance to Inertial Confinement Fusion. Non-linear solitary structures of relevance to space physics, namely phase space electron holes, have also been highlighted by the measurements. These measurements are discussed and compared to existing models.

Spatially Resolved Measurements of Laser Filamentation in Long Scale Length Underdense Plasmas with and without Beam Smoothing

The onset of filamentation, following the interaction of a relatively long (tau(L) similar or equal to 1 ns) and intense (I-L similar or equal to 5 x 10(14) W/cm(2)) laser pulse with a neopentane filled gas bag target, has been experimentally studied via the proton radiography technique, in conditions of direct relevance to the indirect drive inertial confinement fusion scheme. The density gradients associated with filamentation onset have been spatially resolved yielding direct and unambiguous evidence of filament formation and quantitative information about the filamentation mechanism in agreement with previous theoretical modelings. Experimental data confirm that, once spatially smoothed laser beams are used, filamentation is not a relevant phenomenon during the heating laser beams propagation through typical hohlraum gas fills.

Experimental studies of the advanced fast ignitor scheme

Guided compression offers an attractive route to explore some of the physics issues of hot electron heating and transport in the fast ignition route to inertial confinement fusion, whilst avoiding the difficulties associated with establishing the stability of the channel formation pulse. X-ray images are presented that show that the guided foil remains hydrodynamically stable during the acceleration phase, which is confirmed by two-dimensional simulations. An integrated conical compression/fast electron heating experiment is presented that confirms that this approach deserves detailed study. (C) 2000 American Institute of Physics. [S1070-664X(00)02809-3].