The column of a dc arc burning in a metal halide atmosphere

Starting from energy and mass balance (diffusion equation), temperature distributions and plasma compositions are calculated for metal halide discharges in closed cylindrical vessels with and without mercury (buffer gas). Special interest is given to arcs in tin halide atmospheres. While for pure tin halide discharge radiation can be neglected, the energy transfer by radiation must be considered in discharges containing larger amounts of mercury. The results obtained for electrical data as well as for thermal data of Sn–I arcs are in reasonable agreement with the experiments.