Change of electrical conductivity of Ar welding arc under resonant absorption of laser radiation

• Published in: Journal of physics. D, Applied physics Vol. 48; no. 9; pp. 95502 - 11
• Main Authors: Kozakov, R, Emde, B, Pipa, A V, Huse, M, Uhrlandt, D, Hermsdorf, J, Wesling, V
• Format: Journal Article
• Language: English
• Published: IOP Publishing 11.03.2015
• Subjects: Anodes; Arc welding; Current density; Electric potential; Electrical conductivity; Electrical resistivity; Laser beam welding; laser radiation; Resistivity; resonant absorption; temperature; TIG arc
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/48/9/095502

Experimental investigations of the impact of resonant laser absorption by a tungsten inert gas welding arc in argon are presented. The intensity increase of the arc's radiation between the laser entrance height and the anode are observed, as well as the variation of arc voltage due to the presence of the laser beam. High-speed camera recordings from different directions combined with absolutely calibrated spectroscopic measurements allow the reconstruction of the three-dimensional emission coefficient profiles without the assumption of axial symmetry. The obtained data are evaluated within the framework of local thermodynamic equilibrium. The local increase in the temperature and conductivity due to the influence of the laser is determined. Changes in the electrical conductivity obtained from the optical measurements coincide well with the measured voltage drop, and show significant redistribution of the current density profile near the anode in particular.