脉冲电压上升沿对He大气压等离子体射流管内放电发展演化特性的影响  

Effects of pulse voltage rising edge on discharge evolution of He atmospheric pressure plasma jet in dielectric tube

作　　者：朱彦熔 常正实[1] Zhu Yan-Rong;Chang Zheng-Shi(School of Electrical Engineering,Xi’an Jiaotong University,State Key Laboratory of Electrical Insulation and Power Equipment,Xi’an 710049,China)

机构地区：[1]西安交通大学电气工程学院电力设备电气绝缘国家重点实验室,西安710049

出　　处：《物理学报》2022年第2期191-203,共13页Acta Physica Sinica

基　　金：强脉冲辐射环境模拟与效应国家重点实验室开放课题(批准号:SKLIPR1706);国家自然科学基金(批准号:51777165)资助的课题。

摘　　要：通过仿真和实验相结合的手段,以直流脉冲电压驱动的双环电极结构He大气压等离子体射流为例,研究了电压上升沿时间对管内放电等离子体发展演化特性的影响.随着电压上升沿的改变,管内介质阻挡放电(dielectric barrier discharge,DBD)区出现空心和实心两种放电模式.上升沿为纳秒和亚微秒量级时,以空心模式发展,上升沿持续增加后转变为实心模式.放电模式本质上受鞘层厚度、管内电场和表面电荷密度分布的影响,鞘层厚度小于1.8 mm时等离子体通常以空心模式传播,等于1.8 mm时等离子体的径向传播范围有限而转变为实心传播.管内DBD区,电场以轴向分量为主时,等离子体以放电起始时的模式传播;而在地电极内部,由于外施电场方向发生径向偏转,同时管壁沉积的正电荷形成径向自建电场,两者叠加形成的强径向电场致使放电以空心模式传播.In this work,we employ pulse voltage to drive an atmospheric pressure plasma jet(APPJ) in Helium,and consider mainly the evolution of discharge inside tube.Specifically,the effects of rising edge on the discharge evolution are studied through the simulation and experiment.The spatiotemporal evolution of electron density,ionization source,electron temperature and excited helium atom are evaluated.Besides,the mechanism affecting the rise time is analyzed by the parameters such as discharge current,sheath thickness and surface charge density distribution.In the considered cases,the ionization wave propagates to the ground electrode and downstream of the active electrode in the dielectric tube.The plasma with faster rising edge has larger electron temperature,discharge current,electron density and electric field strength.With the change of voltage rising edge,there occur two discharge modes:hollow mode and solid mode in dielectric barrier discharge(DBD) area.When the rising edge is of nanosecond and sub microsecond,it develops into hollow mode,and changes into solid mode after the rising edge has continued to increase.Both discharge modes are essentially affected by the sheath thickness,the electric field distribution,and the surface charge density inside the tube.When the sheath thickness is less than 1.8 mm,the plasma usually propagates in hollow mode,and when the sheath thickness is equal to 1.8 mm,the radial propagation range of the plasma is limited and changes into solid propagation.In the DBD region,when the electric field is mainly axial component,the plasma propagates in the mode at the beginning of discharge;inside the ground electrode,owing to the fact that the applied electric field is deviated from the radial direction,and that the positive charge deposited on the tube wall forms a radial self-built electric field,the strong radial electric field formed by the superposition of the two fields causes the discharge to propagate in hollow mode.

关 键 词：He大气压等离子体射流 放电模式 等离子体鞘层 上升沿时间 

分 类 号：O53[理学—等离子体物理]