Study of electron emission at the cathode in an arc discharge

Abstract

The work presented in this paper is devoted to the study of the phenomena of electron emission that take place at the cathode in an electric arc discharge. This problem remains a subject of careful research conducted by several specialists. Nevertheless, it seems interesting to make a comparison between all the theories currently available. In an electric arc, electrons are emitted from the surface of the cathode. The cathode spot is the place from which the electrons emerge. The current density of the electrons emitted represents 90% of the total current density. The remaining 10% is provided by the positive ions present in front of the cathode. Thus, the determination of the total current density at the cathode in an arc discharge is reduced to the calculation of that of the emitted electrons. The choice of the method for calculating the current density of the electrons emitted at the cathode is crucial for the evaluation of the total current density at the cathode. In our model, the current density of emitted electrons is evaluated using the Murphy-Good formulation which is in the current state, the most general and the most accurate equation.