Plasma state in free-burning argon arc and its effect on anode heat transfer

Abstract

In order to make clear the physical grounds of deviations from local thermodynamic equilibrium (LTE) in atmospheric free-burning argon arcs, the heavy particle temperature, electron temperature and LTE temperature obtained from electron number density were measured by use of line-profile analysis of the laser scattering method without an assumption of LTE. The experimental results showed that the core region of the arc significantly deviated from LTE under both conditions of 50 and 150 A in arc current. As a result, it is suggested that the deviations from LTE in the arc core should be affected strongly by the cathode jet and that aspects of the anode heat transfer were greatly changed by the plasma state in the arc core.