电爆金属丝质量密度分布的演变过程

基于X-pinch软X射线辐射点源对直径10 m钨丝单丝以及8 m钨丝双丝电爆发展过程进行了背光成像研究，实验平台为清华大学电机系研制的脉冲功率装置PPG-1（500 kV/400 kA/100 ns）。成像光路安排为：作为X射线源的X-pinch和作为目标物的钨丝分别安装在装置的输出主电极阴阳极之间和回流导电杆处，成像胶片采用高分辨率、高灵敏度的X光胶片。利用自行设计的电流传感器和罗氏线圈对目标物实际流过的电流进行监测，从而计算得8 m钨丝丝爆过程中电导随时间变化的曲线。为了观测电爆金属丝质量密度分布的演变过程，设计了m级厚度的阶梯光楔。通过大量成像实验，获取了丝芯膨胀、晕层等离子体形成及其向外扩张等过程的相关物理图像以及基于原始胶片绘制的质量密度分布图。

Evolution of mass density distribution of electrical explosion of metal wires

The evolution of single-wire and dual-wire electrical explosion of 8 m- and 10 m- W was investigated by X-ray backlighting using the X-pinch as a soft X-ray source. The experiments were carried out on the pulsed power generator PPG-1 (400 kA/500 kV/100 ns) which was designed and constructed by Department of Electrical Engineering of Tsinghua University. The X-pinch as the X-ray source and the tungsten wire as the object are installed between the anode and the cathode and in the place of a current-return rod, respectively. The X-ray films of high resolution and high sensitivity were used to record the results. The current sensor and Rogowski coil of our own design were used to monitor the current. In order to observe the evolution of mass density distribution of the electrical explosion of single-wire of tungsten, the step wedge was designed. By a large number of imaging experiments, the physical images of wire core expansion, the formation and outward diffusion of the coronal plasma and the mass density distribution based on the original film were obtained. The conductance of 8 m-W was also calculated using voltage and current data.