微空心阴极维持放电获取大体积放电等离子体的实验研究

Experimental Investigation on the Large Volume Discharge Plasma Using the Micro-hollow Cathode Sustained Discharge

为在高气压下获得稳定的大体积辉光放电等离子体,将微空心阴极放电(MHCD)作为等离子体阴极获取电子源,引入第2阳极设计为微空心阴极维持放电(MCSD)发生装置,实验研究了微空心阴极维持辉光放电的放电图像、伏安特性曲线以及气压、第1和第2阳极间距以及第2阳极偏置电压对MCSD放电特性的影响。在此实验条件下可以获得长度为3~5 cm,体积高于10 cm^(3),电子数密度为10^(11)cm^(-3)量级的辉光放电等离子体。实验结果表明,随着阴极电流的增加,源自MHCD和第2阳极方向的辉光放电逐渐向放电轴向中心处汇聚,并最终形成MCSD放电。MCSD的形成为MHCD放电与第2阳极辉区放电相互作用的过程。MCSD放电中存在明显的迟滞效应,MCSD湮灭电流明显小于击穿阈值电流。第2阳极偏置电压对MCSD的击穿阈值的影响较大,但是对湮灭电流的影响较小。第2阳极偏置电压越低,MCSD放电的迟滞效应越明显。

In order to obtain stable large volume discharge plasma at high pressures,the second anode is introduced in the electrode system and a micro-hollow cathode sustained discharge(MCSD)is obtained by using a micro hollow cathode discharge(MHCD)as the electron source of plasma cathode.The discharge image and U-I curve are measured.The influences of the pressure,the distance between the first and second anode,and the voltage on the second anode on the discharge characteristics of MCSD are investigated.In the laboratory conditions,glow discharge plasma with a length of 3~5 cm,a volume of 10 cm^(3) and an electron density of 10^(11)cm^(-3) is obtained.The experimental results show that,with the increase of discharge current on the cathode,the discharge from MHCD and from the second anode gradually converges at the axial center of discharge,and finally forms MCSD discharge.The formation of MCSD is a process of interaction between MHCD discharge and second anode glow discharge.There is an obvious hysteresis effect in the discharge of MCSD,and the annihilation current of MCSD is obviously smaller than the breakdown threshold current.The second anode bias voltage has a significant influence on the breakdown threshold of MCSD,but has a negligible effect on the annihilation current.The lower the second anode bias voltage is,the more obvious the hysteresis effect of MCSD discharge will be.