Reconstruction of Emission Coefficients for a Non-axisymmetric Coupling Arc Based on MALDONADO's Method

The reconstruction of emission coefficient is a key factor for the calculation of temperature field. However, most of the researches for determining arc plasmas are based on axisymmetric sources, little has been done to study non-axisymmetric arc plasmas. In order to reveal temperatures of a non-axisymmetric coupling arc, the distribution of emission coefficients must be reconstructed in advance. In this paper, the argon atomic line intensities of the coupling arc are obtained by using the imaging system that involves a high speed camera in conjunction with a neutral and a narrow-band filter. The converted programme between emission coefficients and emitted intensities is programmed based on MALDONADO's method. A displaced Gaussian model is used for evaluating the validity of the converted programme. Then, the emission coefficients of a free burning arc are reconstructed by MALDONADO's method and an Abel inversion, respectively, and good agreement is obtained. Finally, the emission coefficient profiles of the coupling arc are achieved. The results show that the distribution of emission coefficient for the coupling arc is non-axisymmetric. The emission coefficient profile is similar to an ellipse, and the short axis of the ellipse is in the direction that the two electrodes are arranged along. The peak temperature of the coupling arc is in the middle of both electrodes. There is a strong interaction between both arcs within the coupling arc. The proposed research solves difficulties for determining asymmetric arcs and enlarges the application scope of spectroscopic techniques.