in Large Helical Device - IAEA Atomic and Molecular Data Unit

IAEA Technical Meeting on Atomic, Molecular and Plasma Material Interaction Data for
Fusion Science and Technology
Recent Progress on Tungsten Spectroscopy And Its Data Analysis
in Large Helical Device
S. Morita a, T. Oishi a, I. Murakami a, M. Goto a, X. L. Huang b, D. Kato a,
S. A. Sakaue a, H. M. Zhang b, K. Fujii c, M. Hasuo c, L. H. Hu d, Z. W. Wu d,
L. Zhang d, C. F. Dong e, Z. Y. Cui e
National Institute for Fusion Science, Toki, 509-5292, Japan
Graduate University for Advanced Studies, Toki, 509-5292, Japan
Graduate School of Engineering, Kyoto University, Katsura, Kyoto 615-8540, Japan
Institute of Plasma Physics, Hefei 230031, China
Southwestern Institute of Physics, Chengdu 610041, China
E-mail address of main author:
A comprehensive study of tungsten spectra has been started from 2010 experimental
campaign in Large Helical Device. The tungsten spectra have been observed by injecting
tungsten pellet [1] in three wavelength ranges of visible, VUV and EUV ranges. In the visible
range a magnetic forbidden dipole transition from highly ionized tungsten ions was observed
for the first time in fusion devices [2]. A huge number of tungsten spectra have been also
measured in the visible (3000-7000Å) [3] and VUV (300-3000Å) [4] ranges when the
spectrometer directly observes a tungsten pellet ablation cloud with extremely low
temperature (10eV) and high density (1018cm-3).
In the EUV (10-500Å) range the tungsten spectra have been observed not only the
wavelength spectrum but also radial profiles in the plasma core. The observed tungsten
spectra in the EUV range are identified and analyzed the spectra using HULLAC code. The
radial profile of tungsten spectra is quantitatively analyzed for W44+ and W45+ ions and those
density in plasmas is estimated assuming a pratical ionization balance at measured electron
temperature profile. The observed tungsten ionization stage is compared with a result from
the impurity transport code calculation [5]. A big difference is observed between the
measured and calculated tungsten ionization stages. In order to determine practical ionization
and recombination rates, which are really necessary for the tungsten transport study in fusion
plasmas, the radial profile has been observed for many ionization stages of tungsten ions at
wide electron temperature range, i.e., 0.1Te2.0keV. Some of them are comapred with
impurity transport results. The ionization balance of tungsten ions is discussed in the
coference with newly observed problems in tungsten spectroscopic study [6].
[1] X.L.Huang et al., Rev.Sci.Instrum. 85 (2014) 11E818.
[2] D.Kato et al., Phys.Scripta T156 (2013) 014081.
[3] S.Morita, et al., AIP Conference Proceedings 1545 (2013) 143.
[4] T.Oishi et al., to be published in Appl. Optics 53 (2014).
[5] S.Morita, et al., Journal of Plasma Fusion Research 89 (2013) 289 [in Japanese].
[6] S.Morita et al., “A problem to be solved for tungsten diagnostics through EUV spectroscopy in fusion
devices” NIFS-Proc-95 (2013) 108.
*This work was partly supported by the JSPS-NRF-NSFC A3 Foresight Program in the field of Plasma Physics
(NSFC: No.11261140328, NRF : No. 2012K2A2A6000443).