一种非轴对称磁绝缘电子鞘层边界的计算方法  

A method to calculate the electron sheath profile of the nonaxisymmetrical magnetic insulation

作　　者：魏浩[1,2] 孙凤举[2] 呼义翔[2] 梁天学[2] 丛培天[2] 邱爱慈[1,2] Wei Hao Sun Feng-Ju Hu Yi-Xiang Liang Tian-Xue Cong Pei-Tian Qiu Ai-Ci(State Key Laboratory of Electrical Insulation and Power Equipment, Xi＇an Jiaotong University, Xi＇an 710049, China State Key Laboratory of Intense Pulsed Padiation Simulation and Effect, Northwest Institute of Nuclear Technology, Xi＇an 710024, China)

机构地区：[1]西安交通大学,电力设备电气绝缘国家重点实验室,西安710049 [2]西北核技术研究所,强脉冲辐射环境模拟与效应国家重点实验室,西安710024

出　　处：《物理学报》2017年第3期347-354,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11505138,51577156)资助的课题~~

摘　　要：长距离磁绝缘传输线内电极偏心、感应腔注入电流非均匀分布引起电子鞘层边界偏心等非对称磁绝缘特性.电子鞘层边界是研究非轴对称磁绝缘特性的重要参数.本文提出一种计算非轴对称磁绝缘电子鞘层边界的方法.通过引入角向非均匀分布的模数,将经典一维轴对称Creedon稳态磁绝缘理论推广应用于圆柱坐标系下二维(r,θ)平面.建立了感应电压叠加器次级非轴对称磁绝缘的二维Creedon物理模型,给出了非轴对称磁绝缘电子鞘层边界的数值计算方法和计算误差.当阴极角向磁场(阴极电流)角向分布满足余弦函数时,电子鞘层边界接近高斯分布.阴极电流角向不均匀程度越大,电子鞘层边界偏心程度越严重,计算误差越大.The nonaxisymmetrical magnetic insulation would occur due to the disalignment of inner electrodes in long magnetically insulated transmission lines, or the nonuniform distributions of injected currents in induction cavities of magnetically insulated induction voltage adders（MIVA）. The electron sheath profile is a very important parameter to characterize the nonaxisymmetrical magnetic insulation. In the past, the three-dimensional particle in cell simulation was usually used to determine the electron sheath profile, which is extremely time-consuming and inefficient. In this paper, a fast and efficient calculation method is proposed. The classical one-dimensional Creedon theory of the magnetic insulation equilibrium is generalized to a two-dimensional plane of（r, θ） via introducing a parameter defined as the azimuthal mode number. Two-dimensional Creedon is developed to model the asymmetric magnetic insulation of the MIVA. Provided the azimuthal distributions of magnetic flux density on the cathode, which is in proportion to the cathode current, the two-dimensional Creedon model is numerically solved. A numerical solution method to calculate the electron sheath profile is proposed, and then the calculation error is also given. As the azimuthal distribution of magnetic flux density on the cathode meets a cosine function, the profile of the electron sheath is approximate to the Gauss function. As the nonuniform portion of cathode current increases, the electron sheath becomes more eccentric, and the calculation error is also much larger.

关 键 词：磁绝缘感应电压叠加器 注入电流非均匀分布 非轴对称磁绝缘 电子鞘层边界 

分 类 号：TN811[电子电信—信息与通信工程]