Optical Emission Characteristics of Electrical Explosion of Different Wires in Air

Optical emission during wire explosion process contains much information. The characteristics of electrical explosion of Al, Ti, Fe, Cu, Mo, Ag, Ta, and W wires as well as fine graphite rods were studied under sub-microsecond and microsecond time-scale pulsed currents in air, respectively. Moreover, a test platform containing a diagnostic system was established. With a storage energy of 500 J, wires and rods with a length of 1 cm and a diameter of 200 μm were exploded by pulsed currents with rise rates of ~45 A/ns and ~5 A/ns, respectively. Meanwhile, voltage, current, light intensity, and time-integrated spectrum were recorded. The experimental results reveal that sizeable optical emission starts from voltage collapse and lasts for more than 300 μs. In general, Ti wire load has the strongest optical emission. Non-refractory metals such as Al, Cu, and Ag possess similar optical emission characteristics including light intensity and spectrum. Refractory metals such as Mo, Ta, and W, on the other side, possess similar optical emission characteristics. Although carbon rods have similar light intensity with refractory metals, their spectra resemble those of non-refractory metals. It could be also inferred from the spectra that optical radiation energy between 250 nm to 380 nm is strong, occupying 42.9% for a Cu wire load. Optical emission varies for different loads, indicating the plasma parameters are also different.