Properties of the anode boundary layer in copper vapor at different current densities and pressures

A one-dimensional model for the anode plasma layer in copper vapor is developed. Using this model, the spatial distributions of the anode plasma parameters (the ion and atom densities, the electric field and potential, the temperatures of electrons and heavy particles, and the ion current density) are analyzed for different current densities and pressures. It is also studied how the anode layer parameters depend on the choice of the boundary conditions at the boundary of the sheath region with the quasineutral plasma region. The studies are carried out assuming that ion-neutral collisions in the sheath are important, as well as in the approximation of the collisionless sheath. Different boundary conditions for the electron temperature at the sheath-plasma boundary, usually used in the literature, are considered. The voltage drop in the sheath near the anode surface is also analyzed for different conditions. The results of the calculations are compared with the results on the argon anode layer parameters and found to be in qualitative agreement. The obtained results are relevant for many applications involving plasmas with copper ions and copper atoms, especially arc discharges used in plasma torches for spraying and welding technologies.