Effect of medium pressure and charging voltage on plasma characteristics during microsecond explosion of single metallic wire

Microsecond explosion of metallic wires has drawn attention of many researchers due to its complicated physical process and various applications, such as production of metal nanoparticles1. When a high density pulsed current passes through a thin wire, it quickly melts, vaporizes and ionizes. The medium pressure and charging voltage have significant effect on the development of the generated plasma2. The experiments are carried out in an explosion chamber with backflow rods around the explosion wire. The current is supplied by a capacitor with capacitance of 2 μF charged up to 50kV. The experiments are conducted with wire material of aluminum, the wire diameter of 500μm and the wire length of 2cm. Firstly, different charging voltage is applied in the medium of air of 1bar. The current and voltage waveforms are captured by a self-integrating Rogowski coil and a voltage divider, respectively. The expansion area of the plasma, the wire core and the expansion boundary as well as the shape and velocity of the plasma sheath are recorded through shadowgram, Schlieren image and interferogram. Then, different air pressure of 50mbar, 100mbar, 500mbar and 1bar is applied as the background medium at a fixed charging voltage to investigate the influence of medium pressure on the development of explosion plasma.