Luminous spot distribution of vacuum arc discharge with deuteride cathode

Vacuum arc discharges with deuteride cathode have many applications, such as nondestructive examination, oil logging, and neutron activation analysis. Deuteride cathode releases many gases during discharge, which is quite different from metal cathode. The discharges display some unique characteristics. A maguifying lens and an ICCD camera are used to observe the luminous spots of vacuum arc discharge. The space resolution of this system is about 5 μm, and the time resolution is about 2 ns. The arc current has a full width at half maximum (FWHM) of about 0.9 μs, and its waveform is half cycle sinusoidal. The results show that the luminous spots merge together into a big one in most cases. Sometimes there are two or more luminous spots due to droplets. The area of the luminous spot grows as arc current increases. The cathode spots’ merging is helpful to increase plasma density and improve discharge efficiency.