The temperature profiles in wall-stabilized atmospheric pressure arcs in argon and Ar-CO2 mixture
have been obtained at currents of 5 A to 40 A using spectroscopy techniques. The temperature
profiles were measured using the absolute intensity of spectral lines. The monatomic excitation
temperatures are determined experimentally from three chosen spectral lines of argon (415.86,
427.22, 696.54 nm), spectral lines of carbon (538.03, 477.175 nm) and spectral lines of triple
oxygen (777.19, 777.42, 777.54 nm) in wall-stabilized arc. The results show the plasma had not the
same composition locally as the
gas injected in to the middle of the arc column.
The results obtained are in good agreement with previously published data for pure argon and show
the gradient formation of an arc core and the increase in axis temperature as the gas mixture is
varied from pure argon to Ar-CO2 mixture. Another result of these investigations is to show the
importance of high purity gas when using monatomic gases, the addition of even a few per cent of
CO2 to argon having a drastic effect both upon extinction of the arc according to current values and
upon the temperature profiles.