轴对称平板二极管空间电荷限制流的2维效应

李永东; 何锋; 刘纯亮

强激光与粒子束, 2005, 17 (6): 913, 网络出版: 2006-04-28

轴对称平板二极管空间电荷限制流的2维效应

Two-dimensional geometry effect on space-charge-limited current in axially symmetrical planar diode

论文大纲

李永东何锋刘纯亮

作者单位

西安交通大学电子物理与器件教育部重点实验室,陕西,西安,710049

平板二极管空间电荷限制流粒子模拟 2维效应 Planar diode Space-charge-limited current Particle-in-cell simulation 2D geometry effect

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100 kV和1 MV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.

Abstract

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.

参考文献

[1] Child C D. Discharge from hot Cao[J]. Phys Rev, 1911, 32: 492-511.

[2] Langmuir I. The effect of space charge and initial velocities on the potential distribution thermionic current between parallel plane electrodes[J]. Phys Rev, 1923, 21: 419-435.

[3] Luginsland J W, Lau Y Y, Gilgenbach R M. Two-dimensional Child-Langmuir law[J]. Phys Rev Lett, 1996, 77(22): 4668-4670.

[4] Goplen B, Ludeking L, Smithe D, et al. User-configurable MAGIC for electromagnetic PIC calculation [J]. Comput Phys Commun, 1995, 87: 54-86.

[5] Verboncoeur J P, Langdon A B, Gladd N T. An object-oriented electromagnetic PIC code [J]. Comput Phys Commun, 1995, 87: 199-211.

[6] Watrous J J, Luginsland J W, Sasser G E III. Current and current density of a finite-width, space-charge-limited electron beam in two-dimensional, parallel-plate geometry[J]. Phys Plasmas, 2001, 8: 289-296.

[7] Umstattd R J, Luginsland J W. Two-dimensional space-charge-limited emission: beam-edge characteristics and applications[J]. Phys Rev Lett, 2001,87: 145002.

[8] 刘国治. 二极管空间电荷限制电流修正[J]. 强激光与粒子束, 2000, 12(3): 375-378.
Liu G Z. Modification to space-charge-limited current of intense electron beam diode. High Power Laser and Particle Beams, 2000, 12(3): 375-378.

[9] Tarakanov V P. User manual for code KARAT[M]. Springfield, VA: Berkley Research Associates, Inc, 1992.

[10] Lau Y Y. Simple theory for the two-dimensional Child-Langmuir law[J]. Phys Rev Lett, 2001, 87: 278301.

[11] Rokhlenko A, Lebowitz J L. Space-charge-limited 2D electron flow between two flat electrodes in a strong magnetic field[J]. Phys Rev Lett, 2003, 91: 85002.

[12] 刘纯亮, 张晓金, 李永东, 等. 轴对称系统等离子体数值模拟电荷、电流分配CIC方法[J]. 计算物理, 2001, 18(2):129-132.
Liu C L, Zhang X J, Li Y D, et. al. A volume-weighting CIC method for numerical simulation of axial symmetrical plasma. Chinese J Comput Phy, 2001, 18(2):129-132.

[13] Birdsall C K, Langdon A B. Plasma physics via computer simulation[M]. New York: McGraw-Hill, 1985.

[14] Birdsall C K, Fuss D. Clouds-in-clouds, clouds -in-cells physics for many-body plasma simulation[J]. J Comput Phys, 1969, 3: 494-511.

[15] Humphries S Jr. Charged prticle beams[M]. New York: Wiley, 1990.

李永东, 何锋, 刘纯亮. 轴对称平板二极管空间电荷限制流的2维效应[J]. 强激光与粒子束, 2005, 17(6): 913. LI Yong-dong, HE Feng, LIU Chun-liang. Two-dimensional geometry effect on space-charge-limited current in axially symmetrical planar diode[J]. High Power Laser and Particle Beams, 2005, 17(6): 913.

轴对称平板二极管空间电荷限制流的2维效应

关于本站 Cookie 的使用提示

全站搜索

轴对称平板二极管空间电荷限制流的2维效应

相关论文

相关资讯

关于本站 Cookie 的使用提示

全站搜索