Influence of diffusive processes on the formation of the radial structure of an electric arc in metal vapor

The role of diffusive processes in the establishment of the radial structure of a free-burning electric arc was investigated experimentally and numerically. It is shown that the increased content of plasma-forming particles in the peripheral region of arcs observed in many experiments arises from the inadequacy of the assumption on the plasma equilibrium state. This effect can be attributed to the plasma nonequilibrium established as a result of resonant radiation from the hotter axial region undergoing absorption and reemission at the edge of the arc.