Plasma and Fusion Research

Volume 13, 3402096 (2018)

Regular Articles


Hydrogen Recycling Study with a High Temperature Target in the Divertor Simulation Experiment in GAMMA 10/PDX
Akihiro TERAKADO, Mizuki SAKAMOTO, Naomichi EZUMI, Kunpei NOJIRI, Tomohiro MIKAMI, Satoshi TOGO, Takaaki IIJIMA, Takayuki YOKODO, Keiji SAWADA1), Shinichiro KADO2) and Yousuke NAKASHIMA
Plasma Research Center, University of Tsukuba, Tsukuba 305-8571, Japan
1)
Faculty of Engineering, Shinshu University, Nagano 380-8553, Japan
2)
Institute of Advanced Energy, Kyoto University, Uji 611-0011, Japan
(Received 4 January 2018 / Accepted 1 May 2018 / Published 10 August 2018)

Abstract

Hydrogen recycling with a high-temperature W target has been studied in GAMMA 10/PDX. The V-shaped target with W plates was heated up to 573 K and then exposed to the end-loss plasma. When the target temperature was increased from room temperature to 573 K, the intensities of the Hα and Hβ lines almost doubled even though the electron density increased from ∼ 2.3×1016 m−3 to ∼ 2.6×1016 m−3, an increase of ∼ 12%. On the contrary, the electron temperature did not change at approximately 30 eV. The vibrational temperature was ∼ 3400 K and did not change, thus suggesting that the hydrogen molecules were highly vibrationally excited and that the vibrational level did not change. The intensities of the Q1-branch of the Fulcher-α band almost doubled, thus indicating that the molecular density of hydrogen also doubled. The increase of the Balmer-line intensities with increasing target temperature may be caused by the increase in the excited hydrogen atoms produced by the dissociation of vibrationally excited molecules desorbed from the high-temperature target. This increase in excited hydrogen atoms enhances the overall hydrogen recycling.


Keywords

GAMMA 10/PDX, divertor-simulation experiment, hydrogen recycling, high-temperature target, Fulcher-α band spectroscopy

DOI: 10.1585/pfr.13.3402096


References

  • [1] M. Sakamoto et al., Nucl. Fusion 44, 693 (2004).
  • [2] H. Takenaga et al., Nucl. Fusion 46, 3 (2006).
  • [3] M. Sakamoto et al., AIP Conf. Proc. 1771, 060001 (2016).
  • [4] R.K. Janev, D. Reiter and U. Samm, Collision processes in low-temperature hydrogen plasmas (Juel-4105) Germany (2003).
  • [5] E. Surrey et al., Plasma Phys. Control. Fusion 45, 1209 (2003).
  • [6] B. Xiao et al., Plasma Phys. Control. Fusion 46, 653 (2004).
  • [7] R. Mulliken et al., Rep. Prog. Phys. 8.1, 231 (1941).
  • [8] S. Markelj et al., J. Chem. Phys. 134, 12 (2011).
  • [9] J. Harris et al., Surf. Sci. 105, 2 (1981).
  • [10] M. Capitelli et al., Fundamental Aspects of Plasma Chemical Physics: kinetics (Springer-Verlag New York, 2016) p.57.
  • [11] S. Kado et al., J. Nucl. Mater. 337-339, 166 (2005).