外部磁场对低气压氩气等离子体电子输运特性的影响  

Effect of External Magnetic Field on Electron Transport Properties of Low Pressure Argon Plasmas

作　　者：蔡新景[1] 李博[1] 王新新[2] 邹晓兵[2] 鲁志伟[1] 

机构地区：[1]东北电力大学电气工程学院,吉林省吉林市132012 [2]电力系统及发电设备控制与仿真国家实验室(清华大学电机系),北京市海淀区100084

出　　处：《中国电机工程学报》2016年第22期6286-6293,共8页Proceedings of the CSEE

基　　金：国家自然科学基金项目(51207019)~~

摘　　要：处于外部磁场驱动下等离子体由于改变了其电子加热机制和带电粒子输运特性而具有不同动力学特性。为了研究外部磁场对电子输运特性的影响,该文采用改进的多项近似法解玻尔兹曼方程计算了Ar气体的电子输运特性。首先计算了Ar气体在交叉电磁场下的电子输运系数,发现：随着电磁场间夹角增大,z方向体漂移速度、通量漂移速度、体扩散系数、通量扩散系数、电子平均能量和反应速度均减小。接着分析了电磁场夹角对电子速度分布的影响,结果表明：随着电磁场间夹角增大,电子沿E×B方向和（E×B）×B方向呈聚集趋势;当电磁场间夹角为π/2时,电子速度分布在能量为0.3~0.6e V区间出现＂凹陷＂现象。最后讨论了磁感应强度对电子速度分布的影响,发现：当约化磁感应强度增大时,电子朝E×B方向和（E×B）×B方向运动趋势也变大;当约化磁感应强度足够大时,低能电子反而较少。Plasma dynamics are altered under the influence of electric and magnetic fields crossed at arbitrary angles because electron heating mechanism and charged particle transport properties are changed. In order to investigate the effects of external magnetic fields on electron transport characteristics, the electron transport coefficients of Ar were calculated based on improved multi-term approximation of Boltzmann equation in the paper. Firstly electron transport coefficients of Ar under the influence of electric and magnetic fields were studied. It can be seen that the bulk drift velocity, the flux drift velocity, the bulk diffusion coefficient, the flux diffusion coefficient, electron mean energy, and reaction velocity all decreased as the orientation angle increased. Then the effects of the orientation angle on electron velocity distribution were analyzed. It is shown that the electrons tend to aggregate toward the directions of E × B and（E × B） × B, and there is a sag of electron velocity distribution between the energy of 0.3e V and 0.6e V when the orientation angle equals to π/2. In the end, the effects of magnetic field strength on electron velocity distribution are studied. It is noted that the trend of aggregation toward the directions of E × B and（E × B） × B increases as the reduced magnetic field strength increases, and the low energy electrons are less than the high energy electrons when the reduced magnetic field strength is large enough.

关 键 词：玻尔兹曼方程 多级近似 电子输运系数 外部磁场 碰撞算子 各向异性 电子速度分布 

分 类 号：TM85[电气工程—高电压与绝缘技术]