Gas in Cascade Arc Torch

In the LPCAT process, only an inert gas such as Ar exists in the cascade arc generator, and DC voltage is applied between the cathode and the anode. Therefore, it is a DC discharge of Ar, but it occurs under much higher pressure than in most low-pressure DC discharges, and the gas travels very fast in one direction in the generator. The basic process of ionization of Ar takes place in the cascade arc generator, which can be depicted as follows. 

The creation of excited neutrals by an electron having the same level of energy also occurs simultaneously  

The cathode captures most of Ar , and the anode captures the majority of electrons. When the luminous gas phase created in the cascade arc generator is blown out of the nozzle, the majority of species in the luminous gas jet are excited Ar neutrals and some strayed electrons. 

In the expansion chamber without addition of the second gas, excited species Ar decay by emitting photons, 

Energy of emitting state above ground state, (eV) 

---