中文摘要：

大气压介质阻挡放电常用于产生低温等离子体,其放电特性已成为当前的研究热点.本文针对大气压氦气介质阻挡放电结构建立了流体数值仿真模型,研究其辉光放电脉冲特性.从发光结构、粒子分布和电场分布等方面说明了该类型放电辉光结构的时空演化过程;分别从电子增长率和电场强度分布两个角度比较和分析了该类型放电中阴极位降区范围的定义,并探讨了发光最强点位置与阴极位降区边界的关系,认为利用电场强度分布来定义该类型放电的阴极位降区范围更加合理,且在电流下降沿内,光强最强点始终处于阴极位降区内部.研究了外施电压、阻挡介质二次电子发射系数γ和N2含量对间隙电压、电流密度和阴极位降区特性等的影响规律.发现：在二次电子发射系数γ不变时,阴极位降区宽度与电流密度具有负线性相关关系;利用阴极位降区的伏安特性证明了该类型放电属于亚辉光放电靠近正常辉光放电的部分;主要考虑N2与He的Penning效应时,电流密度和带电粒子密度在一定N2含量下具有最大值等.

英文摘要：

A fluid model is built in this paper to describe and study the atmospheric pressure dielectric barrier glow discharge pulse in helium.The collision excitation and ionization reactions between electron and helium atom,heavy particles reactions,and Penning reaction between N2 and metastable He are taken into account in the fluid model.It is found that there are cathode falling,negative glow,Faraday dark,positive column and anode glow areas in atmospheric pressure glow discharge pulse,and the ranges of different areas are changing during the current falling edge.The ranges of cathode falling area are defined according to electron production balance position（definition 1,set as dc1） and the electrical field distribution around cathode（definition 2,set as dc2）,respectively.Both dc1 and dc2 decreaseas the current grows to its peak in one discharge pulse,which reflects the transition from Townsend discharge to glow discharge.Compared with negative glow peak position,the boundary of cathode falling area by definition 1 is closer to cathode.However,the dc1cannot reflect the cathode potential falling value and lose its definition after current peak moment.The dc2 can reflect the cathode potential falling value but it causes the overlapping between cathode falling and negative glow areas.At the current peak moment,the glow peak is located at the boundary of cathode falling area according to definition 2while the glow peak is always located in the cathode falling area during the current falling edge.The cathode falling area characteristics can be influenced by different factors,e.g.applied voltage,secondary electron emission coefficientγ and N2 content.By changing applied voltage,it is found that the electrical potential dropping in cathode falling area increases as the average current density decreases,which indicates that the atmospheric pressure dielectric barrier glow discharge pulse is a subnormal glow discharge,and it is close to the normal glow discharge region.When 7 〈 0.02,both dc1 and dc2 increase sharpl