Asymmetric Abel Inversion in Imaging Spectroscopy for Tilted TIG Arc Plasma

An asymmetric Abel inversion processing system was developed to establish a method for diagnosing arc plasma that has an elliptical cross section and is a non-axisymmetric in the direction perpendicular to the observation direction during an arc welding process. This method was applied to an arc plasma in a tilted tungsten inert gas (TIG) welding process. As a result, when this method was applied to the non-axisymmetric intensity distribution due to integration, it was confirmed that the relative error near the central axis and the edge was large regardless of the difference in the cross-sectional shape. In addition, after applying this method to the tilted TIG arc plasma, it was shown that an error of about 350 K occurred in the temperature distribution when emission intensity distribution was converted to the temperature distribution by the Fowler-Milne method. Furthermore, the temperature distribution of the arc plasma obtained in this study was slightly wider than the previous study, while the high-temperature area where the temperature was higher than 14000 K showed a good agreement with the previous study. Therefore, it was concluded that, by applying this method to the tilted TIG arc plasma, the equivalent result to the three-dimensional emission spectroscopy could be obtained by photographing a tilted arc plasma from two directions. © 2021 Japan Welding Society. All rights reserved.