霍尔推进器壁面材料二次电子发射及鞘层特性  

Characteristics of wall materials secondary electron emission and sheath in Hall thruster

作　　者：段萍[1] 覃海娟[1] 周新维[1] 曹安宁[1] 刘金远[2] 卿少伟 

机构地区：[1]大连海事大学物理系,大连116026 [2]大连理工大学物理与光电工程学院,大连116024 [3]重庆大学动力工程学院,重庆400030

出　　处：《物理学报》2014年第8期286-292,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11275034;11375039;11175052;11005025);辽宁省科学技术计划重点项目(批准号:2011224007)资助的课题~~

摘　　要：霍尔推进器放电通道等离子体与壁面相互作用形成鞘层,不同壁面材料的二次电子发射对推进器鞘层特性具有重要影响,本文针对推进器壁面鞘层区域建立二维物理模型,研究了氮化硼(BN)、碳化硅(SiC)和三氧化二铝(Al_2O_3)三种不同壁面材料的二次电子发射特性,在改进SiC材料二次电子发射模型的基础上,采用粒子模拟方法,讨论了壁面二次电子发射系数与电子温度和磁场强度的关系,研究了三种材料(BN,SiC和Al_2O_3)的鞘层特性,结果表明:修正的二次电子发射模型拟合曲线与实验曲线几乎一致;在相同电子温度下,三种材料(BN,SiC和Al_2O_3)的二次电子发射系数和壁面电子数密度依次增大,而鞘层电场和鞘层电势降依次减小,BN材料具有合适的二次电子发生射系数,使得霍尔推进器能在低电流下稳态工作。Hall thruster plasma discharge channels interact with wall forming sheath, and different secondary electron emission coefficients of wall material can considerably affect sheath characteristics. In this paper, we establish a two-dimensional physical model in wall sheath area to study the secondary electron emission characteristics of three different wall materials which are boron nitride （BN）, silicon carbide （SiC） and aluminium oxide （Al2O3）, and SiC material secondary electron emission model is improved. On the basis of improved secondary electron emission model, the relationship between the wall secondary electron emission coefficient and both electron temperature and magnetic field intensity is discussed by the particle in cell simulation method, and the different sheath properties of three materials （BN, SiC and Al2O3）, are also investigated. The results show that fitting curve is consistent with the experimental results; at the same electron temperature, the values of secondary electron emission coefficient and electron density of three materials （BN, SiC and Al2O3） increase but the values of sheath electric field and sheath potential drop decrease in their sequence. The BN material has the appropriate secondary electron radiation coefficient, which makes the thruster work steadily under low current condition.

关 键 词：霍尔推进器 壁面材料 鞘层二次电子发射 

分 类 号：O462.2[理学—电子物理学]