Spectroscopic determination of temperature distributions for a TIG arc

The Fowler-Milne or normalized spectroscopic method is used to measure the temperature distribution of a tungsten inert gas (TIG) arc with a number of different spectral lines. The results highlight some of the limitations of this method and provide evidence for departures from LTE in the arc. The paper describes the apparatus and data inversion procedures, and compares the results with those from other groups.