An analysis of cathode spot current density effect on plasma parameters in low-current vacuum arc

摘要

In order to analyze current density effecting on plasma parameters, a cathode spot model isperformed. The cathode spot model assumes that the collisionless sheath and the singly ionizedcollisional plasmas are directly connected. It was found that current density increases withdecreasing arc current. Dependent variables, cathode temperature, electron current fraction,plasma temperature, sheath voltage, plasma density and cathode electric field are increased withincreasing current density. Alternatively, the cathode spot radius is inversely dependent to thecurrent density. These dependent variables are related with to T-F emission and thermionicemission process. This cathode spot model of the present analysis which is used to investigate thecathode spot parameter in low-current vacuum arc may be valid for volatile materials.