Optimized convective heat transfer is applied to accelerate the thermal recovery of a large aperture multi-segment amplifier. The paper proposes a novel project of changing the structural parameters of the inlet jet to the Nd:glass slab in the multi-segment amplifier at the same flow rate. The convective heat transfer coefficient depends on the diameter of the inlet jet, as well as on the number of inlet jets. The simulation calculations indicate that at the same flow rate, different numbers of inlet jet lead to different temperature gradient contours and flow field distributions on the Nd:glass slab surface in the multi-segment amplifier. In addition, the convective heat transfer coefficient increases with the decrease of inlet diameter. This work analyzes the path of the coolant air over the slab surface to lessen the eddy and to achieve better convective heat transfer, as well as to determine the optimized number of inlet jets (5) and the optimized diameter (5 mm)

Beam positioning stability in a laser-driven inertial confinement fusion (ICF) facility is a vital problem that needs to be fixed. Each laser beam in the facility is transmitted in lots of optics for hundreds of meters, and then targeted in a micro-sized pellet to realize controllable fusion. Any turbulence in the environment in such long-distance propagation would affect the displacement of optics and further result in beam focusing and positioning errors. This study concluded that the errors on each of the optics contributed to the target, and it presents an efficient method of enhancing the beam stability by eliminating errors on error-sensitive optics. Optimizations of the optical system and mechanical supporting structures are also presented.

Beam positioning stability in a laser-driven inertial confinement fusion (ICF) facility is a vital problem that needs to be fixed. Each laser beam in the facility is transmitted in lots of optics for hundreds of meters, and then targeted in a micro-sized pellet to realize controllable fusion. Any turbulence in the environment in such long-distance propagation would affect the displacement of optics and further result in beam focusing and positioning errors. This study concluded that the errors on each of the optics contributed to the target, and it presents an efficient method of enhancing the beam stability by eliminating errors on error-sensitive optics. Optimizations of the optical system and mechanical supporting structures are also presented.

The forced convective heat transfer coefficients during the period of thermal recovery for laser slab on the multi-segment amplifies of SG II is analyzed. We simulate the parameters including coolant gas and the geometry of amplifier with computational fluids dynamics (CFD) method. Based on the simulated results, we attain the optimized parameters such as the flow rate, the temperature and the type of gas, the diameter of inlet jet, the quantity of inlet jet, the distance between the inlet jet and the laser slab, and the spray angle of inlet.

The forced convective heat transfer coefficients during the period of thermal recovery for laser slab on the multi-segment amplifies of SG II is analyzed. We simulate the parameters including coolant gas and the geometry of amplifier with computational fluids dynamics (CFD) method. Based on the simulated results, we attain the optimized parameters such as the flow rate, the temperature and the type of gas, the diameter of inlet jet, the quantity of inlet jet, the distance between the inlet jet and the laser slab, and the spray angle of inlet.

从提高结构稳定性的基本理论出发,利用有限元方法研究了靶场桁架结构稳定性。结果表明:影响大口径反射镜动态稳定性的主要因素为靶场桁架的第三阶模态振型,其薄弱环节为支撑立柱;通过在支撑立柱间增加横向加强筋、桁架立柱采用钢管混凝土结构等措施可有效提高桁架的结构稳定性;立柱截面最小方形空心型钢的尺寸为300 mm×6 mm。给出的靶场桁架的稳定性设计方案满足大口径反射镜的动态稳定性指标。

从提高结构稳定性的基本理论出发, 给出了神光Ⅱ升级惯性约束聚变(ICF)靶室系统的初始结构方案, 并利用有限元方法(FMM)对其进行模态分析, 找出靶室系统初始结构的薄弱环节, 进而对初始方案进行结构稳定性优化, 最后对优化方案进行稳定性分析。优化与分析结果表明, 当靶室的壁厚T为50 mm, 靶室支脚与垂直方向夹角θ为27.2°, 支脚之间布置厚度B为20 mm筋板, 筋板空间距离H为120 mm时, 靶室系统可以获得很好的稳定性, 随机激励作用下的平移均方根值为1.425 μm, 满足神光Ⅱ升级装置对靶室系统的稳定性指标。

Structural design and stability analysis of 'phi' 570 mm mirror mount are performed. Under the constraint conditions, the geometric parameters of cross-flexure pivot in large aperture mirror mount are determined. With finite element analysis software (ANSYS), the influences of cross-flexure pivot's setting angle on center drifting and stress distribution of flexure, and the dynamic performance of the whole mirror mount, are analyzed. When the setting angle between the direction of gravity and the setting direction of flexure is 0 or 90 deg., the center drifting of mirror mount is minimum and the stress distribution of flexure is relatively uniform. The nature frequency is 23 Hz, and the maximum amplitude of angular vibration response to random excitation input is 0.91 microrad, which is consonant with experiment results. The performance of mirror mount can satisfy the requirement of precision positioning in Shenguang (SG) II laser system.

In SHENGUANGII (SGII) facility, the optomechanical system is the optics and optomechanical support hardware which necessary to transport the laser beams through the system from the laser drivers to the target. In order to satisfy the laser beam accurately positioned, the system must provide a stable platform for the optical elements before and during a shot. While the ambient vibration such as thermal impact, ground borne, acoustic and noise usually disturbs the stability of the system when the facility on working. This paper put forward the concept of system stability, and the method of test and vibration isolation control presented. The finite element analysis has been used to analysis the stability of the typical system. Base on the result, the working performance of system can be confirm, even the stability of SGII facility in future long-time work can be estimated, also the key points of stability design for the important parts and system can be suggested. It offers design guidance on the next upgrade of SG facility design and guarantee for the procedure of facility’s precision. This information also can be used to the structure and system of the similar facilities.