Difference in oxygen impurity behavior between repetitive short discharges and one long discharge on TRIAM-1M

M. Ogawa, M. Sakamoto, K. N. Sato, H. Zushi, K. Nakamura, K. Hanada, H. Idei, M. Hasegawa, S. Kawasaki, H. Nakashima, A. Higashijima

Research output: Contribution to journalArticlepeer-review

Abstract

Oxygen impurity behaviors of one long duration discharge and repetition of short duration discharges have been investigated in TRIAM-1M. In the former case, the OII line intensity divided by the line averaged electron density, which is considered as a monitor of oxygen concentration on the plasma facing surface (PFS), decreased with the time constant, τd, of 30-50 s during the discharge due to the hydrogen flux to PFS. In the latter case, τd is in the range of 70-600 s. There exists a big difference of global behavior of oxygen impurity between both cases. The difference seems to result from the absence or presence of the interval time between the discharges. The oxygen concentration on PFS increases during the interval time due to adsorption of H2O. The time constant of the increase in the oxygen concentration is evaluated to be about 5500 s from Langmuir adsorption isotherms analysis.

Original languageEnglish
Pages (from-to)1364-1368
Number of pages5
JournalJournal of Nuclear Materials
Volume363-365
Issue number1-3
DOIs
Publication statusPublished - Jun 15 2007

All Science Journal Classification (ASJC) codes

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

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