Mass Density Evolution of Wire Explosion Observed Using X-Ray Backlight

The evolution of single- and dual-wire Z-pinch of 8-μm W was investigated by X-ray backlighting using an X-pinch X-ray source. The experiments were carried out on the pulsed-power generator PPG-I (400 kA/500 kV/100 ns), which was designed and constructed by the Department of Electrical Engineering of Tsinghua University. To scale the mass density distributions at different explosion time, a mass step wedge including eight tungsten layers was fabricated and inserted between the object Z-pinch and the X-ray film. By a large number of imaging experiments, the physical images of coronal plasma formation and interwire plasma merging were obtained. Based on the X-ray photos of 8-μm W and mass step wedge, the mass density distributions at different explosion time were drawn, and the conductance curve of time dependence of 8-μm W was also calculated using waveform of voltage and current.