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1.
The influence of driving frequency on the discharge regime of a homogenous dielectric barrier discharge in argon at atmospheric pressure is studied through a one-dimensional self-consistent fluid model. The simulation results show that the discharge exhibits five notable discharge modes, namely the Townsend mode, stable glow mode, chaotic mode, asymmetric glow, and multiple period glow mode in a broad frequency range. The transition mechanisms of these modes should be attributed to the competition between the applied voltage and the memory voltage induced by the surface charges.  相似文献   

2.
用发射光谱法测量氮气直流辉光放电的转动温度   总被引:4,自引:2,他引:2  
本文报道了氮气气压分别为10和20Pa时,对直流辉光放电的发射光谱进行测量和分析的结果。选择的研究对象为N2放电中形成的N2^ B^2∑u^ →X^2∑g^ 跃迁的Δv=v′-v″=0谱带系中v′=0→v″=0谱带的R支。在阴极背面辉光区、阴极鞘层区、正柱区以及阳极辉光区中分别选择一点进行了转动分辨的发射光谱的测量。利用自己编写的光谱拟合程序,获得了相应的实验条件下N2^ 的转动温度,给出了转动温度随放电电压的变化趋势,其结果可以用直流放电的帕邢定律得到很好的解释。在10和20Pa气压下,放电的阴极鞘层区、正柱区、阳极辉光区中的转动温度都随放电电压呈现出了不同的变化趋势,甚至是完全相反的变化趋势。我们认为这是由于气压不同时,放电状态不同所致:气压为10Pa时的放电是正常辉光放电,而气压为时20Pa的放电为反常辉光放电。  相似文献   

3.
Glow discharge plasmas exhibit various types of self-excited oscillations for different initial conditions like discharge voltages and filling pressures. The behavior of such oscillations associated with the anode glow has been investigated using nonlinear techniques like correlation dimension, largest Lyapunov exponent, etc. It is seen that these oscillations go to an ordered state from a chaotic state with an increase in input energy, i.e., with discharge voltages implying occurrence of inverse bifurcations. These results are different from the other observations wherein the fluctuations have been observed to go from ordered to chaotic state.  相似文献   

4.
Processes in the gas phase of a glow discharge during diode and magnetron reactive sputtering of vanadium in an Ar–O2 atmosphere have been investigated by laser-induced fluorescence (LIF) as a function of the parameters of the glow discharge and the composition of the atmosphere. The intensity of the fluorescence spectra increased by 1.5–2.0 orders of magnitude in the magnetron sputtering process compared with that of diode sputtering. Under continuous sputtering conditions, the dependences of the intensities and relative compositions of the fluorescence spectra on the discharge parameters (discharge voltage and current) have been investigated. In pulsed mode of the glow discharge, the dynamics of changes in the spectra have been studied versus variations in the discharge duration and the lag time for recording the fluorescence signal. The dependence of the spectral line intensities on the partial pressure of oxygen has been found for vanadium and its oxide. The cathode surface at pressures of 0.03–0.04 Pa was shown to convert to the oxidized state.  相似文献   

5.
A new nonlinear effect in a low temperature gas plasma has been found and investigated experimentally. At a critical value of the discharge current in a special glow discharge system the positive column constricts and striations evolve spontaneously. On a large time scale the pattern seems to consist of standing striations. At higher temporal resolution the striations turn out to be moving ones which are modulated by high amplitude oscillations of the total electric current and of the voltage observed at the device. In addition phenomena like period doubling and irregular behaviour occur.  相似文献   

6.
A study is made of the effect of pulse repetition rate (0.1−103 s−1) and average discharge current (0–1 A) on the breakdown delay time and burning voltage of low-pressure glow discharges (p<0.1 Pa) in an electrode system of the reverse magnetron type with a large cathode surface area (≈103 cm2). It is shown that increasing the repetition rate leads to a many-fold reduction in the statistical spread in the delay time and in the discharge formation time, while the average discharge current has a significant effect on the burning voltage. The mechanism for the observed phenomena is interpreted qualitatively in terms of the presence of thin dielectric films on the cathode surface. Zh. Tekh. Fiz. 69, 20–24 (May 1999)  相似文献   

7.
直流辉光放电过程中需要控制的三个重要工作参数为放电电流、放电电压和放电室内氩气气压.该文介绍了一种应用于直流辉光放电等离子体激发光源的自动调节控制系统,该控制系统在放电电流恒定的情况下调节放电室内氩气气压,实现了对放电电压的信号采集和自动控制.文卷阐述了该控制系统的设计思路、电路原理及控制方案.该自动调节控制系统改善了以往用手动调节时精度低且操作复杂的情况,提高了放电电压的控制精度,缩短了放电电压的稳定时间.文中给出了自动控制方式下激发源放电电压的稳定性测试结果,控制精度由手动调节时的4%FS改善为小于1%FS,放电电压稳定时间由手动时的大于90s缩短到30 s以内.采用该控制系统对中低合金钢和锡肯铜标准样品进行了样品精密度实验.元素含量分析精密度比手动调节方式显著提高,各元素含量测试结果的相对标准偏差(RSD)均优于3.5%.中低合金钢标准样品中Ti,Co,Mn元素含量测试结果的RSD范围由手动时的3.0%~4.3%减小到1.7%~2.4%,S和Mo元素RSD范围由5.2%~5.9%减小到3.3%~3.5%.锡青铜标准样品中Sn,Zn,Al元素RSD范围由2.6%~4.4%减小到1.0%~2.4%,Si,Ni,Fe元素的RSD范围由6.6%~13.9%降低到2.6%~3.5%,并给出了实测数据.  相似文献   

8.
俞哲  张芝涛  于清旋  许少杰  姚京  白敏冬  田一平  刘开颖 《物理学报》2012,61(19):195202-195202
在介质阻挡放电体系中产生辉光放电可以有效的提高放电体系产生高能电子的性能, 为等离子体化学反应提供更加丰富的活性粒子.本文对针-板介质阻挡放电体系下的放电模式进行了研究,实验发现放电正负半周期表现出不同的放电模式, 激励电压为3 kV时放电正负半周期分别为微流注放电和电晕放电(或者Trichel脉冲放电),激励电压为6 kV时放电正负半周期分别为微流注放电和微辉光放电.微辉光放电形貌具有与典型辉光放电相同的分层次放电结构, 分析了激励电压6 kV时的放电过程,认为足够强的阴极电场强度和裸露针状电极形成的有效的二次电子发射过程是形成微辉光放电的主要因素,绝缘介质层的存在避免了微辉光放电向弧光放电过渡.  相似文献   

9.
High-power repetitively-pulsed TEA CO2 lasers are excited by a glow discharge, and it turns out to be the arc discharge under some conditions. The arc-discharge is a disadvantageous condition and must be avoided. According to the Faraday electromagnetism induction principle, the arc-discharge monitoring system with a magnetic-field probe is designed for high-power repetitively-pulsed TEA CO2 lasers. The magnetic-field variation induced by the discharge current can be tested, and the discharge state can be distinguished according to the output induction voltage. Experimental results show that the magnetic-field induction voltages generated by a glow discharge and an arc discharge are very different ones. The maximum induction voltage of the glow discharge is 2.0?V, while the minimum induction voltage of the arc discharge is 2.5?C4?V. Three alarm levels are set by measuring the arc-discharge intensities. At the first level, automatic filling?Cexhausting equipment starts to refresh the gas media, at the second level, the laser repetition rate is reduced, and at the third level the laser operation stops immediately. As a result, the working reliability of a high-power repetitively-pulsed TEA CO2 laser system can be improved significantly by using the arc-discharge monitoring system.  相似文献   

10.
The quasi-continuous wide-aperture glow discharge in helium at pressures from 1.2 to 6.0 Torr is studied. It is found that electron beam generation efficiency η is higher than 96% in the pressure range 1.2–3.0 Torr at voltages from 1.0 to 2.6 kV. The maximum power was ≈ 0 kW at 6 Torr and a voltage across the discharge gap of 2.6 kV. Under these conditions, the beam generation efficiency is about 80%. The pressure and voltage dependences of main parameters of the discharge are explained from the standpoint of its photoemission nature.  相似文献   

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