强激光与粒子束, 2018, 30 (8): 085003, 网络出版: 2018-08-21  

阳极杆箍缩二极管的理论模型及物理特性

Theoretical modeling and physical characteristics of rod-pinch diode
作者单位
中国工程物理研究院 流体物理研究所, 脉冲功率科学与技术重点实验室, 四川 绵阳 621999
摘要
闪光X射线源是获得高凝聚态物质内部物理图像的重要手段,阳极杆箍缩二极管(RPD)作为其重要组成部分之一,直接影响闪光X射线源照相质量。研究RPD物理特性对二极管物理结构优化设计及实验调试具有重要意义。分析了RPD空间电荷限制、弱箍缩和磁绝缘阶段物理模型。基于PIC模拟技术,编写了计算程序,研究了RPD不同阶段的电子电流、离子电流及电子束箍缩物理特性。通过理论分析,获得了特定几何结构RPD物理模型修正系数及各个阶段离子电流与电子电流比,验证了粒子模拟代码的有效性。模拟结果表明:空间电荷限制阶段,粒子模拟结果与双极性流计算结果一致;在弱箍缩和磁绝缘阶段,粒子模拟得到的总电流与磁绝缘模型计算结果一致,且与文献给出的经验拟合表达式计算结果一致;磁绝缘阶段离子电流与电子电流之比与电压和二极管几何结构相关,给出了离子电子电流比增大系数η与电压和阴阳极半径比的关系,该系数受电子、离子在不同结构二极管渡越时间的影响,随电压和阴阳极半径比增加而逼近恒定值。
Abstract
The rod-pinch diode (RPD) is a cylindrical pinched beam diode being developed as an intense pulsed small diameter bremsstrahlung source for flash X-ray radiography. The studying significance of the physical characteristics lies in optimizing geometry structure of RPD.Using PIC program and numerical simulation, a model of the rod-pinch diode operation based on space limited current at low voltage and self-magnetically limited current at high voltage is researched. Analysis shows that the diode characteristic is determined by space charge limited current at low voltage and self-magnetically limited critical current at high voltage. The simulation result is consistent with reference. Under the special conditions(space charge limited, weakly pinched and self-magnetically limited), the ratios of ion current to electron current are studied. The coefficient for calculating the self-magnetically limited ion to electron current ratio in the self-magnetically limited condition is affected by the electron and ion transit time and free from the high voltage.
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耿力东, 谢卫平, 袁建强, 王敏华, 曹龙博, 付佳斌, 赵小明, 何泱. 阳极杆箍缩二极管的理论模型及物理特性[J]. 强激光与粒子束, 2018, 30(8): 085003. Geng Lidong, Xie Weiping, Yuan Jianqiang, Wang Minhua, Cao Longbo, Fu Jiabin, Zhao Xiaoming, He Yang. Theoretical modeling and physical characteristics of rod-pinch diode[J]. High Power Laser and Particle Beams, 2018, 30(8): 085003.

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