6533b7defe1ef96bd127696d

RESEARCH PRODUCT

The modelling of the cathode sheath of an electrical arc in vacuum

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description

This paper presents a simple model of the fragment in the cathode electrical arc root taking into account the physical phenomena occuring on the cathode surface and the sheath. The goal is the obtainment of characteristics values of the heat flux, the electrons, and atoms density in the sheath. Computation is carried out on a one-dimensional model with a coupling between the equation obtained in the sheath and an enthalpy model of the cathode to describe the temperature evolution. In the modelling, we introduce a friction zone above the sheath edge to characterize the heavy particle interactions. Numerical simulation shows that the ionic friction phenomenon deriving from ion–atom collision regulates the heat flux lightening the surface, and the crucial necessity to obtain a good evaluation of the cross section of the charge exchange.