等离子体电极普克尔盒电光开关单脉冲过程数值模拟

采用流体模型对等离子体电极普克尔盒(PEPC)电光开关单脉冲过程进行了数值模拟分析.模型包括带电粒子连续性方程、动量守恒方程、电子平均能量方程及空间电位泊松方程.分别采用隐式指数差分格式，超松弛迭代法(SOR)和经典四阶龙格-库塔法(R-K)对带电粒子连续性方程，泊松方程和电子平均能量方程进行数值求解.模拟分析了PEPC单脉冲过程中的带电粒子浓度、电子温度、空间电场、PEPC的放电电流、晶体两侧电压和开关效率的时间演化特性.模型得出了PEPC中气体放电等离子体的微观物理过程与PEPC宏观参量的关系，对设计 关键词： 等离子体电极普克尔盒 电光开关 数值模拟 气体放电     

280mm×280mm口径单脉冲过程电光开关

用于高功率惯性约束聚变(ICF)激光驱动器的大口径电光开关均采用等离子体电极泡克耳斯盒。与传统的等离子体电极电光开关原理不同,单脉冲过程驱动电光开关没有独立的大电流等离子体发生单元,而只是通过具有较高幅值的正负开关脉冲完成对大口径电光开关的驱动。介绍单脉冲过程驱动等离子体电极泡克耳斯盒电光开关的设计,并建立280 mm×280 mm口径电光开关实验平台,利用连续激光器测试了电光开关特性,实验测得该电光开关中心处开关效率为99.3%,开关上升时间为90 ns。     

大口径单脉冲过程驱动电光开关研究进展

用于ICF研究的大型激光驱动器，为了获得高输出通量，用了大量的大口径光学元件，造价昂贵。因此，避免大口径光学元件受到损坏尤其重要。而等离子体电极普克尔盒电光开关是用晶体两侧稀薄气体放电形成的高电导率透明等离子体作电极，可以用薄晶体做到大口径，并具有低损耗、高空间均匀性、高损伤阈值，目前正在建造的几台大型激光系统都将采用其作为级间隔离和反向激光隔离的光开关。     

等离子体电极电光开关大面积辉光放电的产生及其特性

 在电光开关的晶体两侧，用辉光放电产生的高电导率透明等离子体作为施加开关脉冲电压的电极，可大大增加开关的通光口径。利用设计建造的一个80mm×80mm口径的等离子体电极电光开关，研究了用于电光开关中的大面积辉光放电的产生方法及放电特性。描述了等离子体电极普克尔盒的结构、放电室和电极的几何尺寸、放电电路及其参数，实验观测了预电离和工作气压对放电的影响。     

等离子体电极电光开关大面积辉光放电的产生及其特性

在电光开关的晶体两侧,用辉光放电产生的高电导率透明等离子体作为施加开关脉冲电压的电极,可大大增加开关的通光口径。利用设计建造的一个80mm×80mm口径的等离子体电极电光开关,研究了用于电光开关中的大面积辉光放电的产生方法及放电特性。描述了等离子体电极普克尔盒的结构、放电室和电极的几何尺寸、放电电路及其参数,实验观测了预电离和工作气压对放电的影响。     

等离子体电极电光开关实验研究

设计建造了以辉光放电形成的等离子体作电极，通光口径为８０ｍｍ×８０ｍｍ的普克尔盒实验，实验检测了它的开关性能。阐述了普克尔盒的结构，辉光放电等离子体电极的形成，开关驱动脉冲的产生及输出特性，电光开关的开关效率和开关速度的检测方法，给出了典型的实验结果。     

300mm×300mm口径电光开关等离子体电极实验研究

设计并实验了300mm×300mm口径的辉光放电室,利用钮扣阴极和自动预电离条形阴极进行实验,获得了大面积均匀的辉光放电。测量了不同状态下辉光放电的放电延时及等离子电阻。得到了产生大面积均匀辉光放电的最佳条件。     

300mm×300mm口径电光开关等离子体电极实验研究

 设计并实验了300mm×300mm口径的辉光放电室，利用钮扣阴极和自动预电离条形阴极进行实验，获得了大面积均匀的辉光放电。测量了不同状态下辉光放电的放电延时及等离子电阻。得到了产生大面积均匀辉光放电的最佳条件。     

大气压双频氦气放电等离子体特性的数值研究

用一维流体模型研究了大气压双频氦气放电等离子体的特性。数值模拟的结果表明,在单、双频放电中,随着应用电压的增加,电子密度和放电电流都增加。相对于单频放电,双频放电中低频源的耦合效应使得放电中的电流以及电子密度降低。随着低频源电压峰值的增加,电子密度降低,离子通量,电子损失能量以及电子吸收能量均降低;但电子温度和电势随着低频源电压峰值的增加而增加。在相同低频源电压下,随着高频源电压的增加离子流非线性增加。     

300nm×300mm口径电光开关等离子体电极实验研究

设计并实验了３００ｍｍ×３００ｍｍ口径的辉光放电室，利用钮扣阴极和自动预电离条形阴极进行实验，获得了大面积均匀的辉光放电。测量了不同状态下辉光放电的放电延时及等离子电阻。得到了产生大面积均匀辉光放电的最佳条件。     

Analysis of Phase Measurement Errors in Electro-Optic Holography

This paper presents the results of an error analysis in electro-optics holography. These errors include phase measurement errors due to the linear phase shifter errors in static electro-optic holography, and phase measurement errors due to the errors in the vibrating bias amplitude and phase in dynamic electro-optic holography. Through the error analysis, we found that the phase shifting errors in static electro-optic holography are twice as large as those in the conventional 4-bucket phase shifting algorithm, and the phase shifting errors in dynamic electro-optic holography are similar to those in the 4-bucket phase shifting algorithm.     

Mutual Action of Optical Activity and Electro-Optic Effect and Its Influence on the Electro-Optic Q-switch

In this paper, we have studied the mutual action of the optical activity and the electro-optic effect, and its influence on the electro-optic Q-switch. The birefringence (g₃₃/n₀)(/n₀)² resulting from the mutual action is calculated. In the polarization light interferometric experiment setup, the outgoing light intensity expression is given by I = A²₀ cos² (/)(g₃₃/n₀)l – ] + (/)[(–2) + (g₃₃/n₀)(/n₀)²]l, for the optically active crystal on which the voltage is applied.We discuss the influence on the turn-off and turn-on states of the Q-switch caused by the mutual action term (g₃₃/n₀) /n₀)², and the advantage and disadvantage of the two work-manners of the Q-switch (i.e., step-up manner and step-down manner). The synthetic properties of La₃Ga₅SiQ₁₄ electro-optic Q-switch are described in comparison to KD₂PO₄ and LiNbO₃ Q-switches.     

温度对铌酸锂电光相位调制特性的影响

利用折射率椭球基本理论对线性电光效应进行了分析,对单轴晶体铌酸锂电光相位调制器的温度特性进行了研究。通过计算机进行数值模拟计算,分析了加电场时光通过LiNbO3电光调制器后出射光的相位变化与温度间的关系,得出在横向和纵向调制中温度对相位改变的影响。研究发现,无论在横向还是在纵向调制下,入射光偏振方向不同但其各自受温度影响的相位变化趋势大体一致,即随着晶体中温度的增加而增大。计算结果表明,LiNbO3电光调制的最佳使用方案为：电场沿x主轴方向施加,入射光偏振方向为感应主轴x’方向,且LiNbO3电光调制器粟用横向相位调制方式。     

Numerical study on characteristics of nitrogen discharge at high pressure with induced plasma

Based on the fluid theory of plasma, a model is built to study the characteristics of nitrogen discharge at high pressure with induced argon plasma. In the model, the spices such as electron, N₂⁺, N₄⁺, Ar⁺, and two metastable states (N₂ (A³∑_u⁺), N₂ (a¹∑_u^-)) are taken into account. The model includes particle's continuity equations, electron's energy balance equation, and Poisson equation. The model is solved with a finite difference method. The numerical results are obtained and used to investigate the effect of time taken to add nitrogen gas and initially-induced argon plasma pressure. It is found that lower speeds of adding the nitrogen gas and varying the gas pressure can induce higher plasma density, and inversely lower electron temperature. At high-pressure discharge, the electron density increases when the proportion of nitrogen component is below 40%, while the electron density will keep constant as the nitrogen component further increases. It is also shown that with the increase of initially-induced argon plasma pressure, the density of charged particles increases, and the electron temperature as well as the electric field decrease.     

Numerical study on the characteristics of nitrogen discharge at high pressure with induced plasma

Based on the fluid theory of plasma, a model is built to study the characteristics of nitrogen discharge at high pressure with induced argon plasma. In the model, species such as electrons, N2+, N4+, Ar+, and two metastable states (N 2(A3∑u+), N2 (a1 ∑u-)) are taken into account. The model includes the particle continuity equation, the electron energy balance equation, and Poisson抯equation. The model is solved with a finite difference method. The numerical results are obtained and used to investigate the effect of time taken to add nitrogen gas and initially-induced argon plasma pressure. It is found that lower speeds of adding the nitrogen gas and varying the gas pressure can induce higher plasma density, and inversely lower electron temperature. At high-pressure discharge, the electron density increases when the proportion of nitrogen component is below 40%, while the electron density will keep constant as the nitrogen component further increases. It is also shown that with the increase of initially-induced argon plasma pressure, the density of charged particles increases, and the electron temperature as well as the electric field decreases.     

An Innovative Simple Method for Study of the Characteristics of the Trigatron Plasma Switch

A simple Semi‐Analytical method used to fit the experimentally recorded current of the closed switch discharge circuit into the free running under damped LC oscillator model and the arc plasma conductivity, electron density of the plasma and efficiency of the spark gap switch energy transfer have been driven from the model by some simple calculations. The charging voltage, switch pressure and the spark gap has been changed between 6 to 15 kV, 1 to 1.5 bar and 1.4 or 2.8 mm, respectively. The obtained values for plasma conductivity and electron density of plasma are (5‐25)(Ω mm)^–1, (0.5–3.5)·10²⁴m^–3, respectively. The efficiency of the switch is plotted Vs. Pd and E/P which in both cases the peak value has been about 80 present.     

基于有限元法的新结构LiNbO3电光调制器的分析与优化

对传统结构的LiNbO3电光调制器进行了改进,并用有限元法对改进后的电光调制器进行了分析计算,采用T形电极、脊波导和空气背槽的新型LiNbO3电光调制器在进行了结构尺寸优化后,相速完全匹配,带宽可达98 GHz,特性阻抗为52 Ω,损耗系数为0.464 dB/(cm·GHz1/2),半波电压为7.13 V,其性能远优于传统结构的调制器.     

微腔等离子体放电过程的数值研究

采用2维自洽完全流体模型,数值研究了阳极为通孔的高气压微腔放电结构中等离子体参数的变化过程。模拟结果获得了当氩气压强为13.3 kPa时,放电中的电势分布、等离子体密度分布、径向电场分布和电子温度分布等重要参数的演化过程。模拟结果表明在放电过程中,阴极附近的电场由轴向电场逐步转变为径向电场,等离子体密度最大值位于放电腔中间处,并随时间推移由阳极附近向阴极附近移动,电子温度的最大值出现在阴极环形鞘层区域。     

随机过程数值仿真的精度实验与分析

为了考核随机过程数值仿真中采用的混沌多项式展开,小波动态自适应网格等的可靠性和近似程度,本文构造了一个具有解析解的随机过程,随后进行数值仿真。比较了数值仿真结果与解析解,证明两者是相互一致的。说明所采用的数值仿真方法是成立和近似度是可以接受的。所进行比较的随机过程解析解是相对比较简单的,当对更复杂的情况需要进一步数值实验验证。在文中并讨论了影响数值仿真精度和增加数值仿真工作难度的因素。