微空心阴极自脉冲放电微观动力学过程  

Experiment and simulation on spatiotemporal microscopic dynamics of self-pulsing discharge in micro-hollow cathode

作　　者：梁远毅 方振松 贺亚峰[1] 李庆[1] 何寿杰[1] LIANG Yuanyi;FANG Zhensong;HE Yafeng;LI Qing;HE Shoujie(College of Physics Science and Technology,Hebei University,Baoding 071002,China)

机构地区：[1]河北大学物理科学与技术学院,保定071002

出　　处：《物理学报》2025年第5期110-119,共10页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:U23A20678);河北省自然科学基金(批准号:E2022201057);中央引导地方科技发展资金(批准号:236Z1803G);保定市基础研究专项(批准号:2472P003)资助的课题.

摘　　要：为了进一步揭示自脉冲放电机理,本文对氩气环境下的微空心阴极自脉冲放电进行了实验研究.结果表明,随着放电电流的升高,放电分为汤生放电、自脉冲放电和正常辉光放电三个阶段.一个完整的自脉冲放电周期可以分为电流的上升期、下降期以及放电的等待期.本文同时利用流体模型对自脉冲放电的时空动力学特性进行了模拟研究.模拟结果表明,当自脉冲放电电流处于最小值时,放电被限制在阴极孔内,电场强度、电子密度和电子产生速率均较低,为汤生放电模式;随着放电电流的增高,孔内放电逐渐增强,同时放电由孔内逐渐向孔外延伸.当脉冲电流最高时,阴极孔外具有较强的放电,阴极外表面附近形成明显的阴极鞘层,阴极腔外部存在较高的电子产生速率.当放电电流降低时,放电由孔外向孔内收缩,并逐步恢复到汤生放电模式.模拟结果同时表明,不同自脉冲放电阶段电离源不同:电流较高时直接电离起主要作用,电流处于最低值时的脉冲等待期潘宁电离起主要作用.实验和模拟结果表明,微空心阴极自脉冲放电实质上是放电被限制在孔内的汤生放电模式与放电区域延伸到孔外的正常辉光放电模式相互转换的过程.To further explore the mechanism of self-pulsing discharge,a sandwiched microcavity cathode is used to study this phenomenon in argon.With the increases of discharge current,the discharge undergoes Townsend discharge,self-pulsing discharge and normal glow discharge.A complete self-pulsing discharge consists of the rising edge,the falling edge of the discharge current,and the waiting period of the discharge.The spatiotemporal dynamic characteristic of self-pulsing discharge is simulated by using a fluid model.The simulated results indicate that when the self-pulsing discharge current reaches its minimum value,the discharge is confined inside the cathode cavity.The electric field,electron density and electron generate rate are low,resulting in a Townsend discharge mode.As the discharge current increases,the discharge inside the cavity is strengthened,and the discharge gradually extends from the inside of the cavity to the outside.When the current reaches its maximum value,there exists a strong discharge outside the cavity,and an obvious cathode sheath is formed near the outer surface of the cathode,resulting in a high electron generate rate outside the cavity.When the discharge current decreases,the discharge shrinks from the outside to the inside of the cavity,and finally returns to the Townsend discharge mode.The simulated results also indicate that the ionization source varies depending on the stage of self-pulsing discharge,specifically,direct ionization is dominant when the current is high,and Penning ionization plays a major role in the pulse waiting period when the current reaches its minimum value.The experimental and simulation results indicate that the self-pulsing discharge in a micro-cavity cathode is essentially a process of mode transition between the Townsend discharge mode where the discharge is confined within the cavity and the normal glow discharge mode where the discharge region extends to the outside of the hole.

关 键 词：自脉冲放电 微空心阴极放电 模式转换 流体模型 

分 类 号：O461[理学—电子物理学]