Unified modelling of non-equilibrium microarcs in atmospheric pressure argon: potentials and limitations of one-dimensional models in comparison to two-dimensional models

A recently developed modelling approach is applied in one and two dimensions in order to obtain the plasma properties of direct current microarcs in atmospheric pressure argon under non-equilibrium conditions. The configuration includes a cylindrical cathode made of tungsten and a cooled copper anode. The one-dimensional (1D) description represents the situation on the axis of the two-dimensional (2D) axially symmetric arrangement. The models solve equations for species and energy conservation of electrons and heavy particles and the Poisson equation, which are coupled to the heat conduction in the thermionic cathode. The results obtained show very good agreement between the one- and 2D models provided that the microarc plasma fills and solely occupies the inter-electrode space. When the arc attachment spreads to the lateral surface of the cathode, the 1D model can be applied at a reduced current density to explore the plasma in the inter-electrode region. (C) 2020 The Japan Society of Applied Physics