The development of single-wire and multi-wire Z-pinches was investigated by X-ray backlighting using X-pinch as soft X-ray source. The experiments were carried out on the pulsed power generator PPG- I (400 kA/500 kV/100 ns)developed by the Department of Electrical Engineering of Tsinghua University. The X-pinch acting as the X-ray source and the single-wire or multi-wire Z-pinch acting as the object were installed in the place of a current-return rod or the center between the anode and the cathode. The X-ray films of high resolution and high sensitivity were used to record the results. The current sensor and Rogowskicoil of our own design were used to monitor the current. In order to measure the mass ablation rate of the thin wire, the step wedge of micron-level thickness was designed. Through a large number of imaging experiments, the physical images of the plasma merging, the coronal plasma formation and the instabilities development of Z-pinch and some important parameters like mass ablation rate and core expansion rate were obtained.%基于X箍缩软X射线辐射点源对单丝及多丝Z箍缩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-Ⅰ (500 kV/400 kA/100 ns).成像光路安排为:作为X射线源的X箍缩和作为目标物的单丝或多丝(双丝)Z箍缩分别安装在装置的输出主电极阴阳极之间或回流导电杆处,成像胶片采用高分辨力、高灵敏度的X射线胶片.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.为了测定目标物金属细丝的质量消融率,设计了μm级厚度的阶梯光楔.通过大量成像实验,获取了Z箍缩等离子体融合、先驱等离子体形成及不稳定性发展等过程的相关物理图像以及质量消融率、丝芯膨胀率等重要定量参数.
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