Numerical analysis of tungsten erosion and deposition processes under a DEMO divertor plasma

Yuki Homma, Kazuo Hoshino, Shohei Yamoto, Nobuyuki Asakura, Shinsuke Tokunaga, Akiyoshi Hatayama, Yoshiteru Sakamoto, Ryoji Hiwatari, Kenji Tobita, Joint Special Design Team for Fusion DEMO

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

Erosion reduction of tungsten (W) divertor target is one of the most important research subjects for the DEMO fusion reactor design, because the divertor target has to sustain large fluence of incident particles, composed mainly of fuel ions and seeded impurities, during year-long operation period. Rate of net erosion and deposition on outer divertor target has been studied by using the integrated SOL/divertor plasma code SONIC and the kinetic full-orbit impurity transport code IMPGYRO. Two background plasmas have been used: one is lower density ni and higher temperature case and the other is higher ni and lower temperature case. Net erosion has been seen in the lower ni case. But in the higher ni case, the net erosion has been almost suppressed due to increased return rate and reduced self-sputtering yield. Following two factors are important to understand the net erosion formation: (i) ratio of the 1st ionization length of sputtered W atom to the Larmor gyro radius of W+ ion, (ii) balance between the friction force and the thermal force exerted on W ions. DEMO divertor design should take into account these factors to prevent target erosion.

Original languageEnglish
Pages (from-to)323-328
Number of pages6
JournalNuclear Materials and Energy
Volume12
DOIs
Publication statusPublished - 2017 Aug

Keywords

  • DEMO
  • Divertor
  • Erosion
  • Ionization length
  • Thermal force

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Materials Science (miscellaneous)
  • Nuclear Energy and Engineering

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