Abstract
Experiments were conducted upon a 130-A 1.1-atm balanced argon arc over a range of velocities from 5.09 to 13.13 m/s; electrode spacing was 12.7 mm. Two stable modes of operation were found: the colinear mode, with arc attachments fix at the apexes of the electrodes, and the upstream mode, with arc attachments on the upstream sides of the electrodes. Below a critical velocity of about 5 m/s, the colinear mode only was found. For the colinear mode, arc isotherm distributions, cross-sectional shape, and profile varied markedly with distance along its length; these were observed to be relatively uniform for the upstream mode. Significant lateral broadening of both configurations was found. The effect of velocity upon the upstream mode was to decrease the relative broadening of the plasma.