纵向脉冲放电的Ne-CuBr紫外激光参量的数值研究

建立了一个描述纵向脉冲放电的Ne-CuBr紫外激光的动力学模型，数值计算了实验中主要参量对激光性能的影响.给出了激光输出特性随缓冲气压、工作温度和激光管口径之间的变化关系，定量解释了已有的实验结果，为进一步提高激光输出性能提供了依据. 关键词： Ne-CuBr紫外激光 脉冲放电 参量研究     

气体激光器辉光放电及弧光放电的观测

常见的霓虹灯管是最普通的放电管,它那鲜艳的红光是管中氖原子受到电子碰撞激发后所发射的。日常用的日光灯,实际上是汞蒸汽的辉光放电管。He-Ne激光器、CO_2激光器等也都是辉光放电,氩离子激光器虽然是弧光放电,但气压小的弧光则是从辉光放电过渡到大电流密度放电时形成的。工业     

具有空心阴极放电特征的射频放电的两电子组模型

 运用两电子组模型，考虑了射频放电中的α过程和γ过程两种电离机制，并结合流体模型，研究了中等气压下窄电极间隙容性耦合射频放电在运行模式转变区的等离子体密度以及电离速率分布等特性。理论研究表明，γ电离过程在高电流模式运行中起主要作用，并证实了此类放电中存在显著的电子摆钟效应，具有类似于空心阴极放电的特征。     

放电引发的非链式高功率重复频率HF/DF激光器

高功率重频HF/DF激光因其具有的波长和功率优势成为当前中红外激光技术发展的热点之一。介绍了利用紫外预电离横向放电结构和工作气体循环系统建立的放电引发高功率重频HF/DF激光装置。在对激光工作介质SF6/C2H6混合气体放电特性和激光输出特性研究的基础上,开展了强电负性气体的重频均匀体放电技术和气体快速循环置换技术研究,解决了泵浦源重频放电能量在气体介质中的有效沉积和提取问题,实现了激光器50Hz的重频稳定运行和能量稳定输出,HF激光的平均功率达到28W,脉宽100ns,峰值功率5.6 MW。     

飞秒激光引导闪电的模拟实验研究

采用能量40 mJ，脉冲宽度50 fs的超短脉激光脉冲形成的等离子体通道诱发和引导了3—23 cm长间隙的静态高压放电.实验观测显示，等离子体通道整体上能使空气间隙的击穿阈值降低到自然击穿阈值的40％.实验中通过对放电电弧发出的白光信号与激光信号的时间延迟进行分析得到激光引导下梯级先导的发展速度约为10⁷ cm/s. 关键词： 等离子体通道 高压放电     

毛细管放电Z箍缩等离子体X射线激光

毛细管放电Z箍缩等离子体软X射线激光器近几年发展非常迅速，已经获得了在46．9nm的波长上近毫焦量级的激光输出，重复频率达到了4Hz．利用这种软X射线激光在等离子诊断、物质烧熔等方面已开展了初步的应用实验研究．文章介绍了毛细管放电泵浦的两种物理机制，阐述了类氖氩离子2p^53p^1S0-2p^53s^1P1能级间粒子数反转的形成及毛细管放电等离子体柱的演变过程．深入理解这些物理过程，对发展毛细管放电软X射线激光将起到积极作用。     

高重复率脉冲放电金属蒸气激光中电泳对金属蒸气分布的影响

建立了一个理论模型描述了高重复率脉冲放电金属蒸气激光中的电泳动力学过程.得到了稳态和瞬态时金属蒸气密度扩散方程的解析表达式.分别计算了高重复率脉冲放电的He-Sr⁺和He-Cd⁺激光在不同时刻金属蒸气密度的轴向分布过程.结果表明，在放电开始后约2s内即可在阴极区建立起相当均匀的轴向金属蒸气密度分布，从而确保了电泳式金属蒸气激光的稳定输出特性. 关键词： 电泳 高重复率脉冲放电 轴向金属蒸气分布 金属蒸气激光     

放电泵浦ArF准分子激光动力学模拟与参数分析

利用一维流体模型研究了放电泵浦ArF准分子激光动力学过程,得到气体放电过程中放电电路的电流电压波形,得到了电子密度、光子密度、电场的时空分布特性,分析了放电参数对激光输出的影响。结果表明,电路参数、工作气压、氟气比例均对激光输出有显著影响,放电电路中的电感值对输出影响较小,参数范围较广,而电路中较小的峰化电容值有利于获得长脉冲输出,气压太大或太小都会使输出能量降低,同样,氟气比例太大或太小也会使输出能量降低。     

200W二氧化碳激光器

本文叙述稳定的封离型２００Ｗ二氧化碳激光系统，气体比例的配制以及解决冷却过程中放电问题的方法。     

大气压下多脉冲均匀介质阻挡放电的研究

基于一维流体力学模型，数值计算研究了大气压下氦气中多脉冲均匀介质阻挡放电的形成原因和性质，分析讨论了所加电压频率、幅值及介质板性质等对多脉冲均匀放电的影响. 模拟结果显示，当放电间隙较小时，由于介质表面积累电荷增加，感应电场增强，在外加电压的每半个周期内，可以形成多个放电脉冲，这些脉冲相应于等时间间隔的分立击穿. 放电间隙越窄，半个周期内形成的脉冲数目越多. 所加电压频率和幅值的变化不仅影响脉冲的幅度，同时也使放电脉冲的数目发生变化，而介质层厚度及介电常数的变化对放电脉冲数目没有明显的影响. 关键词： 大气压均匀放电 介质阻挡放电 数值模拟 等离子体     

High power self-controled volume discharge based molecular lasers

An investigation was made of the characteristics of the formation of a selfcontroled volume discharge for the pumping of CO₂ lasers, i.e. self-sustained volume discharge (SSVD), which involved a preliminary filling of a discharge gap by an electron flux from an auxiliary-discharge plasma. We have found that this method was suitable for large interelectrode gaps, that distortion of the electric field in the gap by the space charge of the electron flux played an important role in the formation of the discharge and that the electrodes could be profiled dynamically during propagation of an electron flux through the discharge gap and a SSVD could form in systems with a strongly inhomogeneous field. High power SSVD based CO₂ laser systems have been created and investigated. Another type of self-controled volume discharge without pre-ionization, i.e. a selfinitiated volume discharge (SIVD), in nonchain HF lasers with SF₆−C₂H₆ mixtures was investigated as well in our review. We have established that, after the primary local electrical breakdown of the discharge gap, the SIVD spreads along the gap in directions perpendicular to that of the electric field by means of the successive formation of overlapping diffuse channels under a discharge voltage close to its quasi-steady state value. It is shown that, as new channels appear, the current flowing through the channels formed earlier decreases. The volume occupied by the SIVD increases with increase in the energy deposited in the plasma and, when the discharge volume is confined by a dielectric surface, the discharge voltage increases simultaneously with increase in the current. The possible mechanisms which explain the observed phenomena, namely the dissociation of SF₆ molecules and electron attachment SF₆ molecules, are examined. A simple analytical model, which makes it possible to describe these mechanisms at a qualitative level, was developed. High power SIVD based HF(DF) lasers have been developed and tested.     

Numerical simulation and experimental validation of a direct current air corona discharge under atmospheric pressure

Air corona discharge is one of the critical problems associated with high-voltage equipment. Investigating the corona mechanism plays a key role in enhancing the electrical insulation performance. An improved self-consistent multi-component two-dimensional plasma hybrid model is presented for the simulation of a direct current atmospheric pressure corona discharge in air. The model is based on plasma hydrodynamic and chemical models, and includes 12 species and 26 reactions. In addition, the photoionization effect is introduced into the model. The simulation on a bar-plate electrode configuration with an inter-electrode gap of 5.0 mm is carried out. The discharge voltage-current characteristics and the current density distribution predicted by the hybrid model agree with the experimental measurements. In addition, the dynamics of volume charged species generation, discharge current waveform, current density distribution at an electrode, charge density, electron temperature, and electric field variations are investigated in detail based on the model. The results indicate that the model can contribute valuable insights into the physics of an air plasma discharge.     

Numerical simulation and experimental validation of direct current air corona discharge under atmospheric pressure

Air corona discharge is one of the critical problems associated with high-voltage equipment. Investigating the corona mechanism plays a key role in enhancing the electrical insulation performance. An improved self-consistent multi-component two-dimensional plasma hybrid model is presented for the simulation of a direct current atmospheric pressure corona discharge in air. The model is based on plasma hydrodynamic and chemical models, and includes 12 species and 26 reactions. In addition, the photoionization effect is introduced into the model. The simulation on a bar-plate electrode configuration with an inter-electrode gap of 5.0 mm is carried out. The discharge voltage– current characteristics and the current density distribution predicted by the hybrid model agree with the experimental measurements. In addition, the dynamics of volume charged species generation, discharge current waveform, current density distribution at an electrode, charge density, electron temperature, and electric field variations are investigated in detail based on the model. The results indicate that the model can contribute valuable insights into the physics of an air plasma discharge.     

介质阻挡放电中体放电和沿面放电的光谱线形研究

在放电间隙较大的介质阻挡放电中,利用高速照相机,同时观察到了体放电(VD)和沿面放电(SD)。采用光谱法,研究了VD和SD的光谱线形随放电参数的变化。在氩气介质阻挡放电中,测量了VD和SD的Ar Ⅰ(2P₂→1S₅)谱线展宽和频移随气压及放电间隙的变化。结果发现：SD的展宽和频移均比VD的大,说明SD的电子密度高于VD的电子密度;随着压强从40 kPa增大到60 kPa,VD和SD的谱线展宽及频移均增加,表明它们的电子密度均随压强的增大而升高;随着d值从3.8 mm增大到4.4 mm,VD和SD的谱线展宽也增加,反映它们的电子密度均随d值的增大而增加。     

介质阻挡放电中单个新型放电丝放电特征和光谱测量

在放电间隙较大(d=3.8 mm)的介质阻挡放电(DBD)中,通过减小放电区域(S=1 cm×1 cm),首次观察到了单个新型放电丝。与其他实验小组所观察到的单个放电丝相比,该单个新型放电丝由体放电(VD)和沿面放电(SD)二部分构成,其放电稳定性和持续性极好。利用高速照相机和光谱仪,研究了单个新型放电丝在外加电压半周期单次放电中的放电特征和单个新型放电丝侧面放电柱不同位置的等离子体状态。在高速照相机不同曝光时间条件下拍摄得到了单个新型放电丝端面和侧面放电的瞬时照片,并对其外加电压半周期单次放电的放电特征与辉光放电进行了对比。利用发射光谱法,采集了单个新型放电丝侧面放电柱不同位置的氩原子763.26 nm(2P₆→1S₅)和772.13 nm(2P₂→1S₃)发射谱线,并通过两条谱线强度比法,估算出了相应的电子激发温度。实验结果得出：单个新型放电丝由体放电和沿面放电构成,且沿面放电在体放电四周呈枝状扩散;单个新型放电丝在外加电压半周期单次放电中与辉光放电特征相似,且在阴极呈现出漏斗状放电;氩原子谱线强度及其相应的电子激发温度从极板两端到中间均呈减小的变化趋势,表明单个新型放电丝侧面放电柱不同位置的等离子体状态不同。     

Study of ozone generation in an atmospheric dielectric barrier discharge reactor

Ozone (O₃) generation in a dielectric barrier discharge (DBD) reactor driven by a pulsed power supply was investigated at atmospheric pressure and room temperature. An O₃ generation efficiency model is established in which discharge power, O₂ concentration, gas flow rate, and volume of the discharge space are included. Constants in the O₃ generation efficiency model were obtained by fitting the model with experiment results. O₃ concentration can be simply calculated from the energy density and initial O₂ concentration. Comparison on O₃ concentrations from calculation with references is given.     

气体激光器放电等离子体管的新设计

文中分析了常用气体激光器采用园柱形放电管时所存在的弊端,提出了按照光腔类型和模体积来设计放电等离子体管的原理。从而可提高激光器的基模输出功率(TEMoo)。文中给出了管型的设计程序和成形工艺,讨论了具有模体积几何形状放电等离子体管的特性。     

氮气/氨气的高压快脉冲放电光谱研究

本文测量了氮气、氨气及其混合气体的快脉冲放电等离子体的光谱,用光谱分析方法研究了等离子体成分及其与气压和配比的关系,并讨论了在制备氮化物时使用氮、氨混合气体的有利之处。     

微空心阴极放电的流体模型模拟

采用流体模型研究了微空心阴极放电(MHCD)的特点，对放电中电场的形成，电子和离子的密度分布，电子能量分布进行了数值模拟.该计算是针对高气压，圆筒形阴极结构下的He放电.结果表明放电中存在空心阴极效应，从电子能量分布可以看出，放电中存在高能电子，放电空间的电场分布主要表现为径向电场.此外，通过改变气压，阴极孔径等参数计算出它们对放电的影响.分析表明减小孔径有利于负辉区更充分的重合.提高气压将缩短阴极位降区. 关键词： 微空心阴极放电 流体模型     

Characterizing uniform discharge in atmospheric helium by numerical modelling

One-dimensional fluid model of dielectric barrier discharge (DBD) in helium at atmospheric pressure was established and the discharge was numerically simulated. It was found that not only the spatial distributions of the internal parameters such as the electric field, the electron density and ion density are similar to those in a low-pressure glow discharge, but also the visually apparent attribute (light emission) is exactly the same as the observable feature of a low-pressure glow discharge. This confirms that the uniform DBD in atmospheric helium is a glow type discharge. The fact that the thickness of the cathode fall layer is about 0.5mm, much longer than that of a normal glow discharge in helium at atmospheric pressure, indicates the discharge being a sub-normal glow discharge close to normal one. The multipulse phenomenon was reproduced in the simulation and a much less complicated explanation for this phenomenon was given.