金属丝电爆炸晕层等离子体密度的激光色散干涉诊断方法

Laser Dispersion Interferometry Method for the Diagnosis of Corona Plasma Density in Electrical Explosion of Wires

摘要

针对金属丝电爆炸中，晕层等离子体密度结构与时空演化对能量沉积及不稳定性的影响，基于激光色散干涉原理研制了一套具有高灵敏度与连续时间分辨能力的电子密度诊断系统，以实现对低密度晕层等离子体参数的精确连续测量。利用1 064nm与532nm双波长共轴传播及磷酸钛氧钾晶体倍频技术，实现了无需参考臂的共光路稳定测量。通过对银单丝电爆炸过程的多点诊断，成功获取了径向4、12、15mm处，晕层等离子体的电子密度随时间的演化数据。研究结果表明：系统的电子线密度测量下限可达10¹³ cm^-2数量级，测量误差小于5%，相较于传统的马赫-曾德尔干涉法提升了近2个数量级，具备在强电磁干扰环境下，对低密度等离子体的精准诊断能力。随着径向距离从4mm增加至15mm，电子密度峰值从8.5×10¹⁶ cm^-2下降至0.7×10¹⁶ cm^-2；根据探针距离计算得出晕层前沿平均膨胀速度约为82.7km·s^-1，并反推得到等离子体有效产生时刻约为34ns，证实了晕层等离子体的形成先于电压波形的崩塌时刻，在金属丝核心发生剧烈相变前，表面已率先形成低密度的导电通道。该结果为深入理解初期的电流分流机制，及后期不稳定性发展的初始扰动源提供了关键的实验依据，为建立精确的金属丝电爆炸的芯晕结构模型奠定基础。

Abstract

To investigate the influence of corona plasma density structure and spatiotemporal evolution on energy deposition and instability in the electrical explosion of wires, an electron density diagnostic system with high sensitivity and continuous temporal resolution was developed based on the principle of laser dispersion interferometry, to achieve accurate and continuous measurement of low-density corona plasma parameters. By utilizing the coaxial propagation of 1 064nm and 532nm dual-wavelength lasers and the frequency doubling technique of potassium titanyl phosphate (KTP) crystal, stable common-path measurement without a reference arm was achieved. Multi-point diagnosis was carried out on the electrical explosion process of single silver wires, and the temporal evolution data of electron density of corona plasma at radial distances of 4mm, 12mm and 15mm were acquired. The results show that the lower detection limit of the system for electron line density reaches the order of 10¹³ cm^-2 with a measurement error of less than 5%. Compared with traditional Mach-Zehnder interferometry, the detection performance is improved by nearly two orders of magnitude, enabling accurate diagnosis of low-density plasma in strong electromagnetic interference environments. As the radial distance increased from 4mm to 15mm, the peak electron density decreased from 8.5×10¹⁶ cm^-2 to 0.7×10¹⁶ cm^-2. Based on the probe distances, the average expansion velocity of the corona front was calculated to be approximately 82.7km·s^-1, and the effective generation time of plasma was inversely deduced to be about 34ns. It was confirmed that the formation of the corona plasma precedes the collapse of the voltage waveform, and that a low-density conductive channel is preferentially formed on the wire surface before the violent phase transition of the wire core. These results provide crucial experimental evidence for an in-depth understanding of the early current shunting mechanism and the initial perturbation source of subsequent instability development, and lay a foundation for an accurate core-corona structure model for electrical explosion of wires.

关键词

激光色散干涉 / 金属丝电爆炸 / 电子密度诊断 / 晕层等离子体 / 芯晕结构

Key words

laser dispersion interferometry / electrical explosion of wires / electron density measurement / corona plasma / core-corona structure

参考文献

[1] 邱爱慈，吴坚，孙凤举，等. Z箍缩动力学行为及其直接驱动型脉冲源研究进展[J]. 中国电机工程学报，2024，44（17）：7007-7023.

[2] Qiu Aici, Wu Jian, Sun Fengju, et al. Research progress on Z—pinch dynamics and its direct—driven pulsed power technology[J]. Proceedings of the CSEE, 2024, 44(17): 7007-7023.

[3] 吴坚，李兴文，邱爱慈，等. 金属丝电爆炸研究进展：Ⅰ 真空环境[J]. 高电压技术，2018，44（6）：1898-1906.

[4] Wu Jian, Li Xingwen, Qiu Aici, et al. Review of electrical exploding wires: Ⅰ in vacuum[J]. High Voltage Engineering, 2018, 44(6): 1898-1906.

[5] 李兴文，晁攸闯，吴坚，等. 水中金属丝电爆炸冲击波一维数值模拟[J]. 西安交通大学学报，2015，49（4）：1-5.

[6] Li Xingwen, Chao Youchuang, Wu Jian, et al. One—dimensional simulation for shock waves generated by underwater electrical wire explosion[J]. Journal of Xi’an Jiaotong University, 2015, 49(4): 1-5.

[7] 陈紫维，吴坚，姜志远，等. 铝单丝在可调预脉冲作用下的Z箍缩动力学行为实验和数值模拟研究[J]. 中国科学：物理学力学天文学，2023，53（7）：40-50.

[8] Chen Ziwei, Wu Jian, Jiang Zhiyuan, et al. Experimental and numerical studies on the dynamic behavior of single aluminum wire Z—pinch co—driven by the adjustable prepulse and main pulse currents[J]. Scientia Sinica (Physica, Mechanica & Astronomica), 2023, 53(7): 40-50.

[9] Lebedev S V, Beg F N, Bland S N, et al. Effect of discrete wires on the implosion dynamics of wire array Z pinches[J]. Physics of Plasmas, 2001, 8(8): 3734-3747.

[10] 姜志远，卢元博，王威，等. 耦合旋转回流柱的Z箍缩动态轴向磁化模型及其结构优化方法[J]. 西安交通大学学报，2025，59（5）：198-208.

[11] Jiang Zhiyuan, Lu Yuanbo, Wang Wei, et al. Z—pinch dynamic axial magnetization model of coupled rotating reflux column and its structural optimization method[J]. Journal of Xi’an Jiaotong University, 2025, 59(5): 198-208.

[12] Zhao Yiming, Wu Jian, Jiang Zhiyuan, et al. Electron density measurement in low—density plasma of electrical wire explosion using a shack—Hartmann wavefront sensor[J]. Review of Scientific Instruments, 2025, 96(9): 093506.

[13] 徐跃生. 激光等离子体干涉实验诊断研究[D].南京：南京理工大学，2007.

[14] Mao Zhiguo, Zou Xiaobing, Wang Xinxin, et al. Evolution of the electrically exploding wire observed with a Mach—Zehnder interferometer[J]. Applied Physics Letters, 2009, 94(18): 181501.

[15] Nejdl J, Vančura J, Boháček K, et al. Imaging Michelson interferometer for a low—density gas jet characterization[J]. Review of Scientific Instruments, 2019, 90(6): 065107.

[16] Liu Yong, Schmuck S, Zhao Hailin, et al. A Michelson interferometer for electron cyclotron emission measurements on EAST[J]. Plasma Science and Technology, 2016, 18(12): 1148-1154.

[17] Qi Niansheng, Prasad R R, Campbell K, et al. Laser wavefront analyzer for imploding plasma density and current profile measurements[J]. Review of Scientific Instruments, 2004, 75(10): 3442-3445.

[18] Qi Niansheng, Fulghum S F, Prasad R R, et al. Space and time resolved electron density and current measurements in a dense plasma focus Z—pinch[J]. IEEE Transactions on Plasma Science, 1998, 26(4): 1127-1137.

[19] Qi Niansheng, Schein J, Thompson J, et al. Z pinch imploding plasma density profile measurements using a two—frame laser shearing interferometer[J]. IEEE Transactions on Plasma Science, 2002, 30(1): 227-238.

[20] Inada Y, Kamiya T, Matsuoka S, et al. Two—dimensional electron density visualization over plasma flare in vacuum breakdown process[J]. Journal of Applied Physics, 2018, 124(8): 083301.

[21] Inada Y, Aono K, Ono R, et al. Two—dimensional electron density measurement of pulsed positive primary streamer discharge in atmospheric—pressure air[J]. Journal of Physics: D Applied Physics, 2017, 50(17): 174005.

[22] Inada Y, Shioda T, Nakamura R, et al. Direct combinational measurements of the electron density and electric field in secondary streamer discharge under atmospheric—pressure air[J]. Physical Review Letters, 2025, 135(24): 245301.

[23] Hopf F A, Tomita A, Al—Jumaily G. Second—harmonic interferometers[J]. Optics Letters, 1980, 5(9): 386.

[24] Fulghum S F, Tilleman M M. Interferometric calorimeter for the measurement of water—vapor absorption[J]. Journal of the Optical Society of America B, 1991, 8(12): 2401-2413.

[25] Licht V, Bluhm H. A sensitive dispersion interferometer with high temporal resolution for electron density measurements[J]. Review of Scientific Instruments, 2000, 71(7): 2710-2715.

[26] Hines N R, Patel S, Scoglietti D, et al. A fiber—coupled dispersion interferometer for density measurements of pulsed power transmission line electron sheaths on Sandia’s Z machine[J]. Review of Scientific Instruments, 2022, 93(11): 113505.

[27] Chavez C T, Egly A, Sepulveda I, et al. Measurement of 2D density profiles using a second—harmonic, dispersion interferometer[J]. Review of Scientific Instruments, 2023, 94(2): 023503.

[28] 汪伟，张海裕，柯链宝，等. 分焦平面式偏振相机偏振误差分析及偏振定标[J]. 光子学报，2024，53（9）：28-39.

[29] Wang Wei, Zhang Haiyu, Ke Lianbao, et al. Polarization error analysis and polarization calibration method for division of focal—plane polarimeter camera[J]. Acta Photonica Sinica, 2024, 53(9): 28-39.

[30] 蒲先坤. 偏振相机阵列计算成像及应用研究[D].合肥：合肥工业大学，2024.

[31] 卢波，史少平，高丽，等. mHz—MHz频段低噪声高增益平衡光电探测器实验研究[J]. 物理学报，2025，74（18）：399-408.

[32] Lu Bo, Shi Shaoping, Gao Li, et al. Experimental research on low—noise and high—gain balanced detectors in mHz—MHz band[J]. Acta Physica Sinica, 2025, 74(18): 399-408.

基金资助

国家自然科学基金资助项目(523B2071)

强脉冲辐射环境模拟与效应全国重点实验室开放基金资助项目(NKLIPR2409)