丝爆等离子体中原子和电子密度分布的激光双波长干涉实验研究  

Experimental Study of Atom and Electron Density Distributions in Wire Explosion Plasma Using Two-wavelength Laser Interferometry

作　　者：黄青丹 王勇 张亚茹 刘静 曾炼 HUANG Qingdan;WANG Yong;ZHANG Yaru;LIU Jing;ZENG Lian(Electrical Power Test&Research Institute of Guangzhou Power Supply Bureau,Guangzhou 510000,China)

机构地区：[1]广州供电局电力试验研究院,广州510000

出　　处：《高电压技术》2020年第9期3284-3291,共8页High Voltage Engineering

摘　　要：为了深入理解真空和空气中铝丝、钨丝的电爆炸的物理过程,需要对电爆炸丝产物中中性原子和电子的密度分布进行定量测量。基于1 kA、0.1 kA/ns脉冲电流源,利用30 ps脉冲激光建立了532 nm和1064 nm的双波长干涉诊断系统,获得了电爆炸产物中的中性原子和电子数密度分布。并根据电压电流测量计算获得了在真空中电爆炸铝丝的欧姆沉积能量接近其气化焓,电爆炸产物以铝原子为主,铝原子密度在轴线处为最大值,沿半径方向衰减。涂层钨丝局部区域可欧姆加热至气化,电爆炸产物的平均电离度小于0.16。实验结果表明:在真空中金属丝电爆炸的产物组分与金属丝材质密切相关,不同材料的金属丝的表面电子发射能力、气化焓差异都将影响着最终的能量沉积与相变过程。电爆炸丝在空气中膨胀产生冲击波,空气的限制作用也使得电爆炸丝边界处出现质量聚集的现象。实验中当电爆炸丝场强>30k V/cm时,在冲击波和电爆炸丝之间的区域可以观察到显著的等离子体通道。空气环境将延迟铝丝的电压击穿时刻,提高金属丝中的欧姆沉积能量。Experiments of the electrical exploding aluminum and tungsten wires in vacuum and air were carried out,and the density distributions of the exploding products were measured.Based on the 1 kA,0.1 kA/ns pulsed current generator,a two-wavelength(532 nm and 1064 nm)laser interferometry system where 30 ps laser was utlized was set up to measure the density distributions of the atoms and electrons.The electrical explosion aluminum wires in vacuum had an ohmic energy deposition close to its vaporization enthalpy,and the explosion products were mainly composed of aluminum atoms.The aluminum atom density had a peak value around its axis,and decreased along its radial direction.Polyimide coated tungsten wires were partially heated to a gaseous state,and its average ionization degree was derived to be less than 0.16.In air,voltage breakdown was delayed and the ohmic energy deposition in the wire was increased.Fast expanding exploded wires would induce shockwaves in air;meanwhile,due to the constraint of air,the exploded wire had a mass accumulation at its border.During the experiments,when the electric field of the wire was greater than 30 kV/cm,a discharge channel was clearly observed in the region between the shockwave and the exploded wire.

关 键 词：电爆炸金属丝 激光双波长干涉 中性原子 自由电子 密度分布 

分 类 号：TN249[电子电信—物理电子学]