Influence of radiation energy losses in a numerical simulation of subsonic vacuum arc in the presence of an axial magnetic field

We present a three-dimensional (3D) Magneto Hydrodynamic Model (MHD) at two temperatures (electronic and ionic) of inter-electrodes plasma, simulated with Ansys Fluent coupled with specific developments in C language. The stationary model describes a subsonic arc in vacuum at 15 kA between copper contacts, submitted to an Axial Magnetic Field (AMF). Due to high temperatures, losses by radiation need to be considered. Even if departures from Local Thermal Equilibrium (LTE) exist, currently due to lack of appropriate data, net emission coefficient data calculated under LTE are used and attributed exclusively to electron energy equation. Two cases are investigated in this study, with or without considering the radiation in the electrons energy equation. The study highlights the importance of better characterizing radiative losses in order to improve the reliability of numerical models.