二次电子分布函数对绝缘壁面稳态鞘层特性的影响  

Effect of wall secondary electron distribution function on the characteristics of stable sheath near a dielectric wall

作　　者：卿绍伟[1] 李梅[1] 李梦杰[1] 周芮[1] 王磊 

机构地区：[1]重庆大学动力工程学院,重庆400044

出　　处：《物理学报》2016年第3期177-184,共8页Acta Physica Sinica

基　　金：中央高校基本科研业务费(批准号:CDJZR13140013;3132014328)资助的课题~~

摘　　要：由于缺乏详细的理论计算和实验结果,在研究绝缘壁面稳态流体鞘层特性时,通常假设壁面出射的总二次电子服从单能分布(0)、半Maxwellian分布等.在单能电子轰击壁面的详细二次电子发射模型基础上,采用Monte Carlo方法统计发现:当入射电子服从Maxwellian分布时,绝缘壁面发射的总二次电子服从三温Maxwellian分布.进而,采用一维稳态流体鞘层模型进行对比研究,结果表明:二次电子分布函数对鞘边离子能量、壁面电势、电势及电子/离子密度分布等均具有明显影响;总二次电子服从三温Maxwellian分布时,临界空间电荷饱和鞘层无解,表明随着壁面总二次电子发射系数的增加,鞘层直接从经典鞘层结构过渡到反鞘层结构.It is widely known that the energy distribution of secondary electrons induced by a single-energy electron beam presents typical bimodal configuration. However, the total velocity distribution of secondary electrons induced by a Maxwellian plasma electron group has not been revealed clearly, due to the lack of detailed theoretical calculation and calculation and experiment result. Therefore, researchers usually function satisfies single-energy distribution（ 0）, halfMaxwellian distribution and so on, in order to study the characteristics of stable fluid sheath near a dielectric wall. For this reason, using the Monte Carlo method to simulate the wall secondary electron emission events based on a detailed probabilistic model of secondary electron emission induced by single-energy incident electron beam, we found that, when the incident electron follows an isotropic Maxwellian distribution, the total perpendicular-to-wall velocity distribution of the secondary electrons emitted from dielectric wall follows a three-temperature Maxwellian distribution. In the simulation, the incident angle of the plasma electrons and the emergence angle of the secondary electrons are considered,so the Monte Carlo method can discriminate whether the secondary electron velocity is perpendicular to or parallel to the wall surface. Then, a one-dimensional stable fluid sheath model is established under the wall boundary condition that the secondary electrons obey the three-temperature Maxwellian distribution; and some contrastive studies are made in order to reveal the effect of wall total secondary electron distribution functions such as single-energy distribution, halfMaxwellian distribution, and three-temperature Maxwellian distribution with the sheath characteristics. It is found that the total secondary electron distribution function can significantly influence the ion energy at the sheath interface, the wall surface potential, the potential and electron/ion-density distributions, and so on. Both the ion energy at sheath interface

关 键 词：鞘层 二次电子分布函数 MONTE CARLO模拟 

分 类 号：O53[理学—等离子体物理]