真空中铝单丝电爆炸的实验研究  

Experimental investigation on the electrical explosion of single aluminum wire in vacuum

作　　者：王坤[1] 史宗谦[1] 石元杰[1] 白骏[1] 李阳[1,2] 武子骞 邱爱慈[1,2] 贾申利[1] 

机构地区：[1]西安交通大学,电力设备电气绝缘国家重点实验室,西安710049 [2]西北核技术研究所,强脉冲辐射环境模拟与效应国家重点实验室,西安710024

出　　处：《物理学报》2016年第1期328-338,共11页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51322706,51237006,51325705);教育部新世纪优秀人才支持计划(批准号:NCET-11-0428);中央高校基本科研业务费专项资金资助的课题~~

摘　　要：开展了铝单丝在负极性电流脉冲作用下电爆炸特性的研究.利用皮秒激光探针,搭建了阴影、纹影和干涉的光学诊断平台,得到了不镀膜铝丝典型的能量沉积过程,在电压崩溃时刻其沉积能量为2.4 eV/atom.为了增加金属丝内的沉积能量,开展了相同电参数及金属丝尺寸下的镀膜铝丝电爆炸实验,其沉积能量可达到5 eV/atom,实现了在电压崩溃之前铝丝完全气化(完全气化所需能量为4 eV/atom).阴影图像展示了高密度丝核区域的膨胀过程,不镀膜铝丝平均膨胀速度为2.2 km/s,而镀膜铝丝因为沉积能量大,其膨胀速度约为不镀膜铝丝的2.3倍,高密度区域膨胀速度为5 km/s.由于阴影不能反映低密度等离子体的膨胀,开展了平行双丝实验,通过测量自发光辐射,估算了低密度等离子体的膨胀速度.利用条纹相机拍摄了不镀膜铝丝电爆炸过程中自发光区域的图像.纹影图像清晰地展示了不镀膜铝丝在电爆炸过程中形成的核冕结构,而镀膜铝丝电爆炸过程中核冕结构得到了一定程度的抑制.从干涉图像计算了相移,在轴对称假设下对相移进行阿贝尔逆变换,重构了三维的铝原子数密度分布.The electrical explosion of single wire occurs in many application fields, such as wire-array Z-pinch, synthesis of the nanopowder, high-intensity magnetic field source, etc. The initial stage of the electrical explosion of single wire has a critical influence on the stagnation and X-ray yield in the wire-array Z-pinch. The impressive result of X-ray yield from wire-array Z-pinch is a major motivation to promote the research in this field. Although numerous studies have been carried out to gain a deep insight into the physics of the electrical explosion of single wire, more experimental investigations are necessary to optimize the energy deposition and expansion rate. It is important to investigate the characteristics of the electrical explosion of single wire under the negative polarity pulsed-current, which is adopted in many Z-pinch facilities. In this paper, the electrical explosion of aluminum wire under negative polarity pulsed-current in vacuum is investigated. In the present experiments, the light emission is measured by the photomultiplier and streak camera. A laser probe EKSPLA-PL2251C（30 ps, 532 nm） is adopted to perform the shadowgraphy, schlieren and interferometry diagnostics. The radial knife-edge schlieren scheme is employed to translate the regions with plasma refractivity and gas-type refractivity. The interferometry is constructed based on Mach-Zehnder interferometer. The shadowgram, schlieren image and interferogram are recorded by Canon cameras. The typical waveforms of the voltage,current and light emission from the electrical explosion of 15 μm-diameter, 2 cm-long aluminum wire are derived. The energy deposition at the instant of voltage collapse is about 2.4 eV /atom（vaporization energy is about 4 eV /atom）.In order to increase the energy deposited into the wire, the 15 μm-diameter, 2 cm-long aluminum wire with 2 μm polyimide coating is exploded with the same electrical parameters. The energy deposition in the coated wire is about5 eV /atom. From the shadowgram of the electrical

关 键 词：单丝电爆炸 光学诊断 Z箍缩 

分 类 号：TG146.21[一般工业技术—材料科学与工程] O539[金属学及工艺—金属材料]