阳极杆箍缩二极管的理论模型及物理特性

耿力东; 谢卫平; 袁建强; 王敏华; 曹龙博; 付佳斌; 赵小明; 何泱

doi:10.11884/HPLPB201830.170425

阳极杆箍缩二极管的理论模型及物理特性

doi: 10.11884/HPLPB201830.170425

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

基金项目:

国家自然科学基金项目 11605183

详细信息

作者简介:
耿力东(1981-), 男, 博士研究生, 主要研究闪光照相技术; glidong809@126.com

通讯作者:
何泱(1986-), 男, 博士, 主要从事脉冲功率技术研究; heyang@caep.cn

中图分类号: TL929
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- 被引次数: 0
出版历程
- 收稿日期: 2017-11-01
- 修回日期: 2018-03-25
- 刊出日期: 2018-08-15

Theoretical modeling and physical characteristics of rod-pinch diode

Key Laboratory of Pulse Power, Institute of Fluid Physics, CAEP, P.O.Box 919-108, Mianyang 621999, China

摘要

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。
- 阳极杆箍缩二极管 /
- 闪光X射线源 /
- 粒子模拟 /
- 电子束 /
- 箍缩特性
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.
- rod-pinch diode /
- flash X-ray radiography source /
- particle-in-cell /
- electron beam /
- pinching characteristics

HTML全文

图 1 RPD物理结构

Figure 1. Schematic illustrating the rod-pinch diode(RPD)

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图 2 RPD的I-V特性(r_C=6.0 mm, L=3.0 mm, r_A=0.75 mm, L_rod=16.0 mm)

Figure 2. The I-V characteristic of the RPD when r_C=6.0 mm, L=3.0 mm, r_A=0.75 mm, L_rod=16.0 mm

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图 3 经验公式与粒子模拟结果

Figure 3. Comparison of diode current between the PIC simulation and empirical formula calculation

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图 4 不同电压下I_e/I_LB与r_C/r_A关系

Figure 4. I_e/I_LB varies with r_C/r_A under different voltage

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图 5 不同电压下I_i/I_e与r_C/r_A关系

Figure 5. I_i/I_e varies with r_C/r_A under different voltage

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图 6 仅考虑电子发射时的二极管物理特性

Figure 6. The physical characteristics of the RPD, only electron emission is considered in PIC simulation

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图 7 考虑电子离子时二极管物理特性

Figure 7. The physical characteristics of the RPD, considering electron and ion emissions in PIC simulation

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图 8 式(20)中系数η与电压的关系(r_C=6.0 mm, L=3.0 mm, r_A=0.75 mm, L_rod=16.0 mm)

Figure 8. Relationship between the coefficient η in Eq.(20) and voltage for r_C=6.0 mm, L=3.0 mm, r_A=0.75 mm, L_rod=16.0 mm

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图 9 离子电子电流比增大系数η与r_C/r_A和r_A的关系

Figure 9. The coefficient η changes with r_C/r_A and r_A

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