摘要
为了研究火花试验装置中电极在真空中放电的微观特性,本文建立了在真空环境下,以钨为阳极材料、镉为阴极材料的二维平行板放电模型.采用PIC/MCC(Particle-In-Cell/Monte Carlo Collision)方法对该模型进行仿真,研究了不同电子发射机制下平行板电极放电的发展过程以及空间场强、阴极表面温度和场增强因子对空间电子变化的影响,得到在场致发射、热发射以及热-场致发射作用下放电过程中的电子浓度和阳极吸收电流的变化以及电子密度和电势的空间分布等.研究发现,场致发射是微间隙阴极电子发射的主导发射机制,当阴极表面温度在焦耳热的作用下达到镉金属的沸点1040K时将产生镉蒸汽,电流密度和电子浓度逐渐增大,此时热发射将开始作用于微间隙放电;当温度大于镉金属气化温度后,场强的影响将大于温度的影响;当场增强因子很小时,热发射几乎不起作用,随着场增强因子不断增大,热发射的作用逐渐增强,导致空间电子浓度明显增加,真空环境下微间隙放电是由热-场共同作用的.
In order to study the micro-characteristics of the electrode discharge in the spark test device in vacuum,this paper established a two-dimensional parallel plate discharge model in a vacuum environment with tungsten as the anode material and cadmium as the cathode material.We simulate the model with the PIC/MCC(Particle-In-Cell/Monte Carlo Col⁃lision)method,studies the development process of parallel plate electrode discharge under different electron emission mech⁃anisms and the influence of space field strength,cathode surface temperature and field enhancement factor on the changes of space electrons,and obtains the field emission,thermal emission and thermal-field emission changes in the electron con⁃centration and anode absorption current during the discharge process,as well as the spatial distribution of the electron densi⁃ty and electric potential,etc.The research has found that field emission is the dominant emission mechanism of micro-gap cathode electron emission.When the cathode surface temperature reaches 1040K,the boiling point of cadmium metal under the action of Joule heat,cadmium vapor will be generated,and the current density and electron concentration will gradually increase.At this time,the thermal emission will start to act on the micro-gap discharge.When the temperature is greater than the vaporization temperature of cadmium metal,the influence of the field strength will be greater than that of the tem⁃perature.When the field enhancement factor is very small,the thermal emission is almost ineffective.As the field enhance⁃ment factor continues to increase,the effect of thermal emission gradually increases,leading to a significant increase in the spatial electron concentration.The micro-gap discharge in a vacuum environment is caused by the combined effect of heat and field.
作者
王党树
栾哲哲
古东明
刘树林
董振
王新霞
WANG Dang-shu;LUAN Zhe-zhe;GU Dong-ming;LIU Shu-lin;DONG Zhen;WANG Xin-xia(School of Electrical and Control Engineering,Xi'an University of Science and Technology,Xi'an,Shaanxi 710054,China;School of Science,Xi'an University of Science and Technology,Xi'an,Shaanxi 710054,China)
出处
《电子学报》
EI
CAS
CSCD
北大核心
2021年第12期2449-2457,共9页
Acta Electronica Sinica
基金
国家自然基金面上项目(No.51777167),国家自然基金青年项目(No.51604217)。
