Global particle balance and wall recycling properties of long duration discharges on TRIAM-1M

M. Sakamoto, M. Yuno, Sanae Itoh, Kazuaki Hanada, Kazuo Nakamura, H. Zushi, Eriko Jotaki, Makoto Hasegawa, S. V. Kulkarni, A. Iyomasa, S. Kawasaki, H. Nakashima

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

The longest tokamak discharge, with a duration of 11 406 s (3 h 10 min), has been achieved. The global particle balance has been investigated. In the longest discharge, the global balance between the particle absorption and release of the wall was achieved at t ∼ 30 min. After that, the plasma density was maintained by the recycling flux alone until the end of the discharge. The maximum wall inventory is about 3.6 × 1020 H at t ∼ 30 min, but it is finally released from the wall at the end of the discharge. The hydrogen release seems to be caused by the temperature increase in the whole toroidal area of the main chamber. Moreover, it has been observed that there is a large difference between the properties of wall recycling in the continuous gas feed case (i.e. static condition) and in the additional gas puff case (i.e. dynamic condition). In the static condition, the effective particle confinement time increases to ∼10 s during the 1 min discharge and it increases to ∼100 s before the global balance in the longest discharge. In the dynamic condition, the decay time of the electron density just after the gas puff, i.e. the effective particle confinement time, is constant at 0.2-0.3 s during the discharge. The large difference in the effective particle confinement time between the static and dynamic conditions seems to be caused by the reduction in the recycling coefficient due to the enhanced wall pumping resulting from the additional gas puff.

Original languageEnglish
Pages (from-to)693-698
Number of pages6
JournalNuclear Fusion
Volume44
Issue number7
DOIs
Publication statusPublished - Jul 1 2004

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recycling
gases
time constant
plasma density
pumping
chambers
decay
hydrogen
coefficients

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

Cite this

Global particle balance and wall recycling properties of long duration discharges on TRIAM-1M. / Sakamoto, M.; Yuno, M.; Itoh, Sanae; Hanada, Kazuaki; Nakamura, Kazuo; Zushi, H.; Jotaki, Eriko; Hasegawa, Makoto; Kulkarni, S. V.; Iyomasa, A.; Kawasaki, S.; Nakashima, H.

In: Nuclear Fusion, Vol. 44, No. 7, 01.07.2004, p. 693-698.

Research output: Contribution to journalArticle

Sakamoto, M, Yuno, M, Itoh, S, Hanada, K, Nakamura, K, Zushi, H, Jotaki, E, Hasegawa, M, Kulkarni, SV, Iyomasa, A, Kawasaki, S & Nakashima, H 2004, 'Global particle balance and wall recycling properties of long duration discharges on TRIAM-1M', Nuclear Fusion, vol. 44, no. 7, pp. 693-698. https://doi.org/10.1088/0029-5515/44/7/001
Sakamoto, M. ; Yuno, M. ; Itoh, Sanae ; Hanada, Kazuaki ; Nakamura, Kazuo ; Zushi, H. ; Jotaki, Eriko ; Hasegawa, Makoto ; Kulkarni, S. V. ; Iyomasa, A. ; Kawasaki, S. ; Nakashima, H. / Global particle balance and wall recycling properties of long duration discharges on TRIAM-1M. In: Nuclear Fusion. 2004 ; Vol. 44, No. 7. pp. 693-698.
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