Observation of arc modes in a magnetically rotating arc plasma generator

An arc plasma can presentvariousforms undertheinfluence of an external magnetic field. In this study, a magnetically rotating arc plasma generator has been developed to produce three arc modes, namely rigid arc, distorted arc, and diffuse arc, which are obtained by controlling the gas flow rate. The evolution of these arc modes are experimentally studied and discussed. Results show that, as the gas flow rate increases, the arc mode is first transformed from the rigid to the distorted mode, and then to the diffuse mode. Comparisonsshow that the location of the arc attachment is a key factor in determining the rigid and distorted modes. The diffuse arc is observed under larger gas flow rates, but the completely diffuse arc can exist only withina narrowrange of gas flow rates. Compared to the distorted arc, the diffuse arc has not only betterstability but also a wider high-temperatureplasma zone, which indicates that the diffuse mode may be more useful in industry.