Calculating the Stark Broadening of Welding Arc Spectra by Fourier Transform Method
PAN Cheng-gang1,2, HUA Xue-ming1,2, ZHANG Wang1,2, LI Fang1,2, XIAO Xiao1,2
1. Welding Engineering Technology Research Institute of Materials Science and Engineering，Shanghai Jiaotong University, Shanghai 200240, China 2. Shanghai Key Laboratory of Materials Laser Procesing and Modification (Shanghai Jiaotong University), Shanghai 200240, China
Abstract：It’s the most effective and accurate method to calculate the electronic density of plasma by using the Stark width of the plasma spectrum. However, it’s difficult to separate Stark width from the composite spectrum linear produced by several mechanisms. In the present paper, Fourier transform was used to separate the Lorentz linear from the spectrum observed, thus to get the accurate Stark width. And we calculated the distribution of the TIG welding arc plasma. This method does not need to measure arc temperature accurately, to measure the width of the plasma spectrum broadened by instrument, and has the function to reject the noise data. The results show that, on the axis, the electron density of TIG welding arc decreases with the distance from tungsten increasing, and changes from 1.21×1017 cm-3 to 1.58×1017 cm-3; in the radial, the electron density decreases with the distance from axis increasing, and near the tungsten zone the biggest electronic density is off axis.
[1] Zielińska S, Musiol K, Dzierzega K, et al. Plasma Sources Science and Technology, 2007, 16: 832. [2] Ribic B, Burgardt P, DebRoy T. Journal of Applied Physics, 2011, 109: 083301. [3] Vervisch P, Cheron B. Journal of Physics D: Applied Physics，1990，23: 1058. [4] Liu L, Huang R, Song G, et al. Plasma Science, IEEE Transactions，2008，36：1937. [5] Gao H, Ma S, Xu C, Wu L. Optical and Plasma Physics，2008，47：191. [6] XIA Yuan, SONG Yong-lun, HU Kun-ping(夏 源，宋永伦，胡坤平). Welding(焊接), 2008, 12: 21. [7] Zielinska S, Pellerin S, Dzierzega K, et al. Journal of Physics D: Applied Physics，2010，43：434005. [8] Torres J, Van De Sande V, Van Der Mullen J. Spectrochimica Acta Part B: Atomic Spectroscopy，2006，61: 58. [9] Torres J, Jonkers J, Sande M J, et al. Journal of Physics D: Applied Physics，2003，36：L55. [10] GUO Zeng-yuan, ZHAO Wen-hua(过增元, 赵文华). Arc and Thermal Plasma(电弧和热等离子体). Beijing: Science Press(科学出版社), 1986. [11] Griem H R. Plasma Spectroscopy. New York: McGraw-Hill, 1964. 1. [12] Griem H R. Spectral Line Broadening by Plasmas. New York: Academic Press, Inc. (Pure and Applied Physics, Volume 39), 1974. 421. [13] ZHU Pei-chen, XIA Meng-fen(朱沛臣, 夏蒙棼). Progress in Physics(物理学进展), 2001，21: 88. [14] Pelleriny K M S, Pokrzywkax B，Chapelley J. Stark width of 4p[12]-4s[32] Ar I transition (696.543 nm), 1996. [15] Vogman G V, Shumlal U, Golingo R P, et al. Stark Broadening Density Profile Measurements Using Fourier Expansion Deconvolution, APS-DPP Meating Atlanta, 2009. [16] Vogman G, Shumlak U. Review of Scientific Instruments，2011，82：103504. [17] LENG Jian-hua(冷建华). Fourier Transform(傅里叶变换). Beijing: Tsinghua University Press(北京：清华大学出版社), 2004. [18] He J, Zhang C. Journal of Optics A: Pure and Applied Optics，2005，7：613. [19] Letchworth K L, Benner D C. Journal of Quantitative Spectroscopy and Radiative Transfer，2007，107：173. [20] Schnick M, Füssel U, Hertel M, et al. Journal of Physics D: Applied Physics，2010，43: 022001.
