空气中大气压下均匀辉光放电的可能性

利用介质阻挡电极结构,对101325×105Pa气压下空气间隙中的放电进行了实验研究,数值模拟计算了实验条件下电子雪崩的发展过程.结果表明:对于长度不大于2mm的空气间隙,可能实现辉光放电.对于长度不小于5mm的空气间隙,如果不能设法降低放电场强,放电必然是流注形式,不可能实现辉光放电.另外,实验结果未能验证“离子捕获”机理降低放电场强而实现辉光放电的正确性 关键词： 大气压辉光放电 电子雪崩 流注     

Langmuir双探针诊断Ne辉光放电管电子密度

应用Langmuir双探针诊断理论,对充有氖气的石英放电管中的辉光放电等离子体进行了诊断,通过实验测得伏安特性曲线,计算得出电子温度和电子密度,讨论了等离子体的宏观参量与电子温度和电子密度的关系.采用直径为0.1 mm的探针对等离子体进行诊断,不仅减小了对所测等离子体区域的扰动,而且减小了读取伏安特性曲线所带来的误差.     

Dusty plasma in the stratified glow discharge in moderate magnetic field

This article presents the experimental study of dust structures formed in striations of glow discharge in an external magnetic field of up to 10⁴ G, which was created using a cryomagnet. A magnetic field classification based on probe theory is described. In moderate magnetic field, we obtained stable dust structures. The corresponding experimental setup and the experiment itself are described in detail. Special attention was paid to the influence of magnetic field on the change of the diameter and inter‐particle distance of dusty cloud. And, we also determined the dependence of angular velocity of dust rotation on magnetic induction.     

The influence of a radial magnetic field on current-voltage characteristics of toroidal glow discharge

The present paper deals with the influence of a radial magnetic field on different regions of the toroidal glow discharge and with the subsequent changes of the current-voltage characteristics. From the above it is clear that when studying the influence of a transverse magnetic field on the glow discharge it is necessary to understand that the discharge is not a homogeneous unit and the change of current-voltage characteristics involves the total sum of changes of the properties in different regions of the discharge.     

磁控直流辉光等离子体放电特性

本文利用单探针诊断等离子体参数来研究自行设计的磁控直流辉光等离子体实验装置的放电特性, 从而得出电子密度与气体压强、电子密度分布与磁场位型以及磁场强度等的关系. 另外, 用有限元的方法对线圈通电产生的磁场进行数值计算, 模拟出不同接线方式的两种磁场位型分布. 通过实验得出这两种不同的位型的磁场均对等离子体的状态有一定的“控制”作用, 而且这种“控制”作用与现有理论相符合.     

赝火花开关辉光放电腔的粒子模拟与实验研究

给出了赝火花开关所需辉光放电腔的具体要求,对赝火开关辉光放电腔进行了优化设计,并对优化后的放电腔进行了粒子模拟和实验研究。粒子模拟结果表明：此放电腔为辉光放电腔,辉光放电建立时间约18.5 ns;辉光放电时,此放电腔阴极位降占整个电位降的主要部分,且阴极位降区净离子密度为一常数。实验结果显示：此放电腔为辉光放电腔,其工作在Paschen曲线最低点左侧,放电电压随气压的升高而降低;当辉光放电电流为0.14～3.60 mA时,放电模式为正常辉光放电。     

赝火花开关辉光放电腔的粒子模拟与实验研究

 给出了赝火花开关所需辉光放电腔的具体要求,对赝火开关辉光放电腔进行了优化设计,并对优化后的放电腔进行了粒子模拟和实验研究。粒子模拟结果表明：此放电腔为辉光放电腔,辉光放电建立时间约18.5 ns;辉光放电时,此放电腔阴极位降占整个电位降的主要部分,且阴极位降区净离子密度为一常数。实验结果显示：此放电腔为辉光放电腔,其工作在Paschen曲线最低点左侧,放电电压随气压的升高而降低;当辉光放电电流为0.14～3.60 mA时,放电模式为正常辉光放电。     

Emission characteristics of a glow discharge plasma based on a mixture of helium with chlorine molecules

We present the results of a study of the emission characteristics of a longitudinal glow discharge based on a mixture of helium and chlorine. Study of the emission characteristics of the discharge showed that it emits most efficiently in the bands of the chlorine molecule with maxima at 200 nm and 258 nm in an He-Cl₂ mixture (P = 0.2–0.3 kPa). We present the optimization of the average emission power of a UV emitter as a function of the glow discharge parameters, the pressure, and the composition of the working gas mixture. Based on solution of the Boltzmann equation for the electron energy distribution function in a discharge based on the optimal mixture (according to experimental data), we calculated the power losses per unit pressure going toward elementary processes, the electron transport characteristics, the ionization and attachment coefficients as a function of the parameter E/P. The calculated parameters of the plasma for the UV emitter allowed us to provide a basis for the qualitative pattern of physicochemical processes in the studied plasma. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 1, pp. 121–124, January–February, 2008.     

基片下磁场磁控对溅射辉光及薄膜梯度的影响

溅射时在基片下方放置磁铁，让来自基片下方的磁场发挥磁控作用，以此来研究基片下磁场磁控溅射的方法.发现辉光形貌以及沉积的薄膜厚度分布均发生明显变化的同时，辉光的外形也随着外加磁铁直径的变化而变化.运用磁荷理论对空间磁场分布进行模拟，解释了辉光形貌变化的机理；运用沉积粒子在外加梯度磁场中运动理论解释了膜厚分布. 关键词： 磁控溅射 辉光 磁场模拟 膜厚梯度     

On the effect of a longitudinal magnetic field on oscillatory characteristics of a subnormal region in discharge in argon

Oscillating nature of current pulses under d.c. excitation in subnormal region with longitudinal magnetic field at pressure range 0.20 torr to 0.85 torr have been studied. The frequency, bandwidth, peak-peak voltage, cut-off current and rise time of the current pulses have been observed with pressure, average tube current and magnetic field. A study of these oscillograms in magnetic field, average tube current and pressure are presented. The probable mechanism for the generation of oscillation based on space-charge field modification with magnetic field is discussed     

Numerical simulation of a direct current glow discharge in atmospheric pressure helium

Characteristics of a direct current(DC) discharge in atmospheric pressure helium are numerically investigated based on a one-dimensional fluid model. The results indicate that the discharge does not reach its steady state till it takes a period of time. Moreover, the required time increases and the current density of the steady state decreases with increasing the gap width. Through analyzing the spatial distributions of the electron density, the ion density and the electric field at different discharge moments, it is found that the DC discharge starts with a Townsend regime, then transits to a glow regime. In addition, the discharge operates in a normal glow mode or an abnormal glow one under different parameters, such as the gap width, the ballast resistors, and the secondary electron emission coefficients, judged by its voltage–current characteristics.     

Electron impact ionization and excitation rate coefficients in the negative glow region of a glow discharge

Some easy to use reasonable approximations for electron impact rate coefficients have been considered. The most important rate coefficients for electron collisions in noble gases are electron-neutral ionization and electron impact excitation. Electron-neutral ionization besides electron impact excitation of some states of the argon and helium atom in direct current (dc) glow discharge plasma has been calculated. The plasma parameters of electron are significant factors for computing the rate coefficients. We present first results of probe diagnostic that includes the double probe measurements of the plasma parameters, namely, electron temperature (T_e) and electron density (n_e). Electron properties obtained from the double probe characteristic curves including T_e and n_e as well as the calculated rate coefficients (ionization and excitation) were studied as a function of the axial distance from the cathode while the discharge operating parameters of voltage and pressure were varied. Two regions of the glow discharge were investigated: cathode fall region and negative glow. Particular emphasis was placed on the negative glow region.     

Low pressure toroidal glow discharge in a radial magnetic field

By measuring the force acting on a flag suspended in a plasma flow the plasma velocity has been estimated. For case when η ? σ B²_r Kracík's theory has been verified experimentally.     

He-O2高气压下电容耦合辉光放电数值分析

采用一维的等离子体流体力学模型研究了氦气-氧气高气压下电容耦合放电过程。分别给出了间隙为1.6,2.4和3.2 mm时外加电压的有效值与放电电流有效值特征曲线,并与已有的实验数据作对比,结果表明计算得到的电压-电流特征曲线与实验数据符合得很好。研究发现：氦气-氧气高气压下电容耦合放电过程中荷质比较大的离子在鞘层中的分布随着外电场的变化而变化,而荷质比较小的粒子在整个放电区域基本不随外电场变化而变化;同时杂质形成正负离子在主等离子体区域两端出现了峰值。     

Time dependent argon glow discharge treatment of Al-alloy samples

Aluminium alloy ultra-high vaccum system provides a convenient tool to access the UHV region due to short pump down time, its reduced weight, low cost etc. For UHV systems, aluminium and its alloys are preferred materials to stainless steel. A cylincrical discharge chamber of SS 304 with various ports on it, evacuated by turbomolecular pumping unit is used in the experimental system. A hollow cathode de glow discharge in argon for different time durations is used to treat chemically cleaned ASA 6063 aluminium alloy samples, keeping all other parameters constant. The scanning electron microscope (SEM) is used to examine processed surfaces and to study topographical features. The energy dispersive microanalysis by X-rays (EDX) is used to determine the elemental composition of the samples. The results indicate the physical sputtering taking place in Ar GDC. The etched area increases with discharge time duration. The EDX spectrum shows the inconsistency in weight percentage of various elements of Al-alloy.     

辉光放电触发赝火花开关的时延及抖动特性

设计了一种辉光放电触发赝火花开关,对其时延和抖动特性进行系统研究。研究了开关时延、抖动与辉光放电电流、气压、触发电压及阳极电压的关系。当辉光放电电流小于0.30 mA时,开关无法触发导通;当电流为0.35~0.60 mA时,随辉光放电电流的增大,开关时延、抖动减小;当辉光放电电流为0.60 mA时,开关时延、抖动基本不变,出现饱和。当氦气气压低于6 Pa,开关难以触通,与理论计算值6.95 Pa吻合;当氦气气压为6~12 Pa时,开关的时延、抖动随气压的升高而减小;气压为12~30 Pa时,开关工作在比较稳定的状态。当触发电压小于3 kV,开关难以触通;随着触发电压的增大,开关时延、抖动减小;当触发电压大于5.3 kV,开关时延、抖动基本保持不变。开关在稳定工作条件下,阳极电压在8~25 kV范围内变化时;开关时延基本不变。     

The effect of a longitudinal magnetic field on the plasma-dust structures in strata in a glow discharge

The plasma-dust structures in strata in a glow discharge exposed to a longitudinal magnetic field are studied in detail. In a weakly ordered structure, the angular velocity has a vertical gradient. A reversal of rotation of the structure in a magnetic field corresponding to the magnetization of electrons is found. With the help of the pair distribution function of particles, changes in the degree of order of the structure in the magnetic field are revealed. These changes correlate with changes in the angular velocity of rotation. To explain this effect, it is assumed that the dust structure is subjected to the action of ions in crossed electric and magnetic fields.     

辉光放电触发赝火花开关的时延及抖动特性

 设计了一种辉光放电触发赝火花开关,对其时延和抖动特性进行系统研究。研究了开关时延、抖动与辉光放电电流、气压、触发电压及阳极电压的关系。当辉光放电电流小于0.30 mA时,开关无法触发导通;当电流为0.35~0.60 mA时,随辉光放电电流的增大,开关时延、抖动减小;当辉光放电电流为0.60 mA时,开关时延、抖动基本不变,出现饱和。当氦气气压低于6 Pa,开关难以触通,与理论计算值6.95 Pa吻合;当氦气气压为6~12 Pa时,开关的时延、抖动随气压的升高而减小;气压为12~30 Pa时,开关工作在比较稳定的状态。当触发电压小于3 kV,开关难以触通;随着触发电压的增大,开关时延、抖动减小;当触发电压大于5.3 kV,开关时延、抖动基本保持不变。开关在稳定工作条件下,阳极电压在8~25 kV范围内变化时;开关时延基本不变。     

雷云电场作用下长地线表面正极性辉光电晕放电的仿真研究

在雷云电场的缓慢作用下, 一种无流注的正极性辉光电晕在接地物体表面起始, 向周围空间注入大量正极性空间电荷, 从而改变雷电先导对雷击目的物的选择. 本文对雷云电场作用下起始于长地线表面的正极性辉光电晕放电进行了仿真研究; 考虑了正极性离子与其他离子的附着与碰撞作用, 建立了一种精确的二维正极性辉光电晕模型; 并通过在实验室内开展高压电晕放电试验, 测量了不同背景电场下的电晕电流; 与本文所建模型的仿真结果进行对比, 对模型的正确性进行了验证. 基于上述模型, 对正极性辉光电晕在雷云感应作用下的起始发展过程与电晕特性进行了仿真模拟, 得到了该电晕的电晕电流、正离子密度分布规律以及正离子迁移规律. 发现在雷云电场作用下, 电晕放电产生的正离子在迁移初期于垂直于地线的平面内基本呈圆对称状均匀分布, 但随着离子逐渐远离地线其分布不再均匀, 呈拉长的椭圆形分布, 多数离子最终分布于地线上方区域并逐渐向雷云方向迁移; 由于正离子在地线上方迁移区聚集形成的正空间电荷背景对行进电子束具有衰减和消耗作用, 抑制了电子崩的形成, 并降低了电子崩转化为流注的概率, 阻止了新的电子崩对流注的不断注入, 同时正空间电荷背景使气体的碰撞面增大, 增加了与电子的复合概率, 引起大量电子的消耗, 最终抑制了电子崩的形成与流注的发展, 地线表面的上行先导得到抑制.