摘要
恒定电流场中电荷面密度的分布特征研究对了解恒定电流的流动特性具有重要意义.利用镜像原理推导出两层无限大导电介质中放置发射和回路电极时在介质交界面和介质与空气交界面上表面电荷密度分布公式.用COMSOL软件数值计算两层导电介质有限大小时的电荷面密度.结果表明,均匀介质中的介质与空气交界面上,发射电极一侧为正电荷,回路电极一侧为负电荷,中间无电荷.两种不同导电介质交界面电荷正负由两侧电阻率差决定,两侧电荷面密度大小与电导率成反比.有限大小介质中,数值计算定量揭示了介质与空气交界面上的角、边和不同介质交界线的电荷分布特性,它们依赖于发射电极和回路电极的位置以及表面几何结构.
The study of the distribution characteristics of the surface charge density in the constant current field plays an important role to understand the constant current field. The mirror principle is used to derive the formula of charge density distribution in two kinds of infinite interfaces （one is the interface of two-layer conductive medium ; another is between the conductive medium and the air） while both emission and return electrode are placed in a conductive medium. By using the software of the COMSOL, the surface charge density under the same circumstance but limited medium is calculated. The results show that on the interface between the medium and air in the homoge- nous medium, one side of the emission electrode is positive charge and the other side is negative, without charge in centre. Whether the charge on the interface between different conductive media is positive or negative is decided by the difference of two side resistivities. The value of the charge density on the interface is inversely proportional to conductivity. In the limited medium, the numerical calculation reveals quantitatively the charge distribution features in corner, edge and intersecting line on the surface. They depend on the position of the emission electrode, the return electrode and the surface geometrical structure.
出处
《大学物理》
北大核心
2013年第2期7-12,21,共7页
College Physics
关键词
恒定电流场
电荷分布
交界面电荷
表面电荷
constant current field
charge distribution
interface charge
surface charge
