Effect of the RF wall conditioning on the high performance plasmas in the Large Helical Device

H. Takahashi, M. Osakabe, K. Nagaoka, H. Nakano, M. Tokitani, K. Fujii, S. Murakami, Y. Takeiri, T. Seki, K. Saito, H. Kasahara, R. Seki, S. Kamio, S. Masuzaki, T. Mutoh

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Abstract The wall conditioning using radio frequency (RF) plasma was carried out using Ion Cyclotron Range of Frequency (ICRF) heating and/or Electron Cyclotron Resonance Heating (ECRH) with the working gas of helium under the established confinement magnetic field. After sufficient numbers of repetitive wall discharge conditioning (DC, ICDC for ICRF and ECDC for ECRH), the formation of the parabolic electron density profile and the increase of the central ion temperature Ti were observed. There was no difference in the attained central Ti of the NBI discharge just after the conditioning using a similar value of input energy regardless of the applied RF source. Thus, it is concluded that both ICDC and the ECDC are effective for the higher Ti plasma production under the established magnetic field in the Large Helical Device. The effective RF wall conditioning scenarios are also investigated for high Ti plasma production.

Original languageEnglish
Article number48727
Pages (from-to)1100-1103
Number of pages4
JournalJournal of Nuclear Materials
Volume463
DOIs
StatePublished - Jul 22 2015
Externally publishedYes

Funding

This work was supported by the NIFS grants , ULRR701, 702, and 703.

FundersFunder number
Japan Society for the Promotion of Science26820399
National Institute for Fusion ScienceULRR701

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