The Study Of Discharge Characteristics About Vacuum Diode Based On PIC Method

Vacuum diode has important applications in many fields,like high voltage(>300k V),strong current(>1k A)electron beams.It is the key component to obtain strong current electron beams,X-rays,gamma rays,high-power microwaves,and high power lasers.The modeling and simulation analysis of vacuum diode is an important research measure,and has been valued by many experts.On the one hand,vacuum arc discharge such as vacuum diode generally contains many nonlinear physical processes,which cannot be accurately solved just by theoretical methods;On the other hand,if we use experimental method to study the discharge characteristics of vacuum diode,it will take too much financial and material resources.Based on the above reasons and the rapid development and application of computer technology,in recent years,a lot of large-scale programs and commercial software have been developed for plasma numerical simulation researches.Based on the ArcPIC particle simulation program,this paper studied the discharge characteristics of cylindrical axisymmetric vacuum diode by PIC-MCC method.The ArcPIC program is a large-scale program developed in 2014 by K.Sjobak and H.Timko of the European Organization for Nuclear Research(CERN)to simulate and analyze the plasma generated by vacuum arc discharge.Firstly,this paper analyzed and introduced the structure of vacuum diode in detail,also gave the specific model and parameters of cylindrical axisymmetric vacuum diode.Then,the basic principles and simulation calculation processes of PIC-MCC method are systematically and in detail analyzed theoretically;Finally,the particle simulation of the cylindrical axisymmetric vacuum diode is carried out based on the ArcPIC program.The plasma and electrical characteristics of the cylindrical axisymmetric vacuum diode are analyzed,and the key influencing factors of discharge characteristics are explored.In addition,the one-dimensional and two-dimensional space charge-limited flows existing in the vacuum diode discharge are analyzed and studied in detail,finally the first-order and second-order relations related to the two-dimensional space charge-limited current density are obtained.In this paper,the combination of theoretical analysis and numerical simulation is used to study the discharge mechanism and discharge characteristics of cylindrical axisymmetric vacuum diode.The electron emission,discharge characteristics,physical processes of plasma generation and diffusion are analyzed.And these may provide a certain technical support and theoretical reference for the theoretical researches or practical applications of vacuum diode.