摘要
应用精度较高的体积加权电荷、电流分配模型,对轴对称平板二极管的空间电荷限制流2维效应进行了粒子模拟研究。选取电压分别为100kV和1MV两种情况,对空间电荷限制流受二极管尺寸影响的规律进行了模拟。模拟结果表明,2维效应使空间电荷限制流密度随二极管形状因子(阴极发射半径与阴阳极间隙的比值)的减小而增大,且受相对论效应的影响不明显。经数值拟合得到了空间电荷限制流2维效应与形状因子相关的二阶经验公式,其一阶系数与一阶理论结果基本一致,约为1/4。
Two-dimensional (2-D) geometry effect on space-charge-limited (SCL) current of an axially symmetrical planar diode was studied with 2.5 D particle-in-cell(PIC) simulation. A volume-weighting cloud-in-cell model was used to improve the accuracy of the PIC method in z-r coordinates system. The simulations with various emitter radii were carried out on the same diode with the applied voltages being 100 kV and 1 MV respectively. The simulation results show that the 2 D geometry effect on SCL current monotonically diminishes with the dimensionless ratio of emitter radius to gap separation, whether in relativistic or non-relativistic regime. When the ratio is more than 0.5, the first-order analytical theory well predicts the limiting current. But when the ratio is no more than 0.5, the second-order correction must be considered.
出处
《强激光与粒子束》
EI
CAS
CSCD
北大核心
2005年第6期913-916,共4页
High Power Laser and Particle Beams
基金
国家863计划项目资助课题
关键词
平板二极管
空间电荷限制流
粒子模拟
2维效应
Computer simulation
Electric currents
Electric potential
Electric space charge
Geometry
Relativity
Two dimensional
