Abstract
In order to make clear the physical grounds for anode fall in atmospheric free-burning argon arc, the results of the experimental measurements of anode fall with Langmuir-probe method for various arc currents and gas flow rates are presented. In the case of low arc current, the anode fall is positive. The electron temperature and space potential rise on approaching the anode surface within 0.1 mm from the anode for low gas flow rate. In the case of high arc current, the anode fall is negative. Furthermore, the electron temperature and the space potential hardly depend on the distance from the anode and are not influenced by gas flow rate.
