中国物理B ›› 2019, Vol. 28 ›› Issue (12): 125201-125201.doi: 10.1088/1674-1056/ab5279

• PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES • 上一篇    下一篇

Estimation of tungsten production from the upper divertor in EAST during edge localized modes

Jing Ou(欧靖), Nong Xiang(项农), Zong-Zheng Men(门宗政), Ling Zhang(张凌), Ji-Chan Xu(许吉禅), Wei Gao(高伟)   

  1. 1 Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China;
    2 Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031, China
  • 收稿日期:2019-07-18 修回日期:2019-10-22 出版日期:2019-12-05 发布日期:2019-12-05
  • 通讯作者: Jing Ou E-mail:ouj@ipp.ac.cn
  • 基金资助:
    Project supported by the National Key R&D Program of China (Grant Nos. 2017YFE0300400 and 2017YFE0301300), the National Natural Science Foundation of China (Grant Nos. 11475223 and 11775257), the National Magnetic Confinement Fusion Science Program of China (Grant No. 2015GB101003), and also partly supported by AHNSF of China (Grant No. 1808085J07).

Estimation of tungsten production from the upper divertor in EAST during edge localized modes

Jing Ou(欧靖)1,2, Nong Xiang(项农)1,2, Zong-Zheng Men(门宗政)1, Ling Zhang(张凌)1, Ji-Chan Xu(许吉禅)1, Wei Gao(高伟)1   

  1. 1 Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, China;
    2 Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031, China
  • Received:2019-07-18 Revised:2019-10-22 Online:2019-12-05 Published:2019-12-05
  • Contact: Jing Ou E-mail:ouj@ipp.ac.cn
  • Supported by:
    Project supported by the National Key R&D Program of China (Grant Nos. 2017YFE0300400 and 2017YFE0301300), the National Natural Science Foundation of China (Grant Nos. 11475223 and 11775257), the National Magnetic Confinement Fusion Science Program of China (Grant No. 2015GB101003), and also partly supported by AHNSF of China (Grant No. 1808085J07).

摘要: During edge localized modes (ELMs), the sheath evolution in front of the Experimental Advanced Superconducting Tokamak (EAST) upper divertor is studied to estimate the sputtered tungsten (W) atoms from the divertor target. A large potential drop across the sheath is formed during ELMs by compared with inter-ELMs, and the maximum of sheath potential drop can exceed one thousand of eV in current EAST operation. Due to the enhancement of the sheath potential drop during ELMs, the W physical sputtering yield from the deuterium (D) ions and the impurity ions on the upper divertor target is found to be significant. It is established that the sputtered W yield during ELMs is at least higher by an order of magnitude than inter-ELMs, and D ions and carbon (C) ions are the main ions governing the W production for the current H-mode with ELMs discharges. With increase in the pedestal electron temperature, the maximum of the D and C ion impact energy during ELMs shows a nearly linear increase, and the D ions have sufficient impact energy to cause the strong W physical sputtering. As a consequence, the D ions may dominate the sputtered W flux from the divertor target when the C concentration is controlled less than one percent for the higher heating power H-mode with ELM discharges in near future.

关键词: sheath, edge localized modes, impact energy

Abstract: During edge localized modes (ELMs), the sheath evolution in front of the Experimental Advanced Superconducting Tokamak (EAST) upper divertor is studied to estimate the sputtered tungsten (W) atoms from the divertor target. A large potential drop across the sheath is formed during ELMs by compared with inter-ELMs, and the maximum of sheath potential drop can exceed one thousand of eV in current EAST operation. Due to the enhancement of the sheath potential drop during ELMs, the W physical sputtering yield from the deuterium (D) ions and the impurity ions on the upper divertor target is found to be significant. It is established that the sputtered W yield during ELMs is at least higher by an order of magnitude than inter-ELMs, and D ions and carbon (C) ions are the main ions governing the W production for the current H-mode with ELMs discharges. With increase in the pedestal electron temperature, the maximum of the D and C ion impact energy during ELMs shows a nearly linear increase, and the D ions have sufficient impact energy to cause the strong W physical sputtering. As a consequence, the D ions may dominate the sputtered W flux from the divertor target when the C concentration is controlled less than one percent for the higher heating power H-mode with ELM discharges in near future.

Key words: sheath, edge localized modes, impact energy

中图分类号:  (Plasma sheaths)

  • 52.40.Kh
52.25.Vy (Impurities in plasmas) 52.40.Hf (Plasma-material interactions; boundary layer effects)