Study of CERC using newly installed 77 GHz gyrotron in LHD

H. Takahashi, T. Shimozuma, M. Yokoyama, T. Ido, S. Kubo, A. Shimizu, Y. Yoshimura, H. Igami, T. Mutoh

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We have investigated the transition to Core Electron-Root Confinement (CERC) using the 77 GHz ECRH system, which was newly installed in the Large Helical Device (LHD). The focal point scan of the ECRH was carried out shot by shot in the same poloidal surface along the magnetic field of 2.75 T, which is the fundamental resonance surface for 77 GHz ECRH. The formation of the steep gradient in the electron temperature and the change of the radial electric field from negative to positive value in the plasma core region were observed by the ECRH injection to ρ<0.5. The foot point of the peaked profile of the electron temperature appeared near the m/n=2/1 rational surface, which was located at ρ∼0.5. These results imply that localized ECRH in the inner region within the lower order rational surface and/or the electron heat flux across the rational surface play important roles for the transition to CERC. We also confirmed that the calculated radial electric field from a neoclassical theory qualitatively agreed with the experimental results.

Original languageEnglish
Title of host publicationRadio Frequency Power in plasmas - Proceedings of the 18th Topical Conference
Pages487-490
Number of pages4
DOIs
Publication statusPublished - 2009
Externally publishedYes
Event18th Topical Conference on Radio Frequency Power in plasmas - Gent, Belgium
Duration: Jun 24 2009Jun 26 2009

Publication series

NameAIP Conference Proceedings
Volume1187
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

Other18th Topical Conference on Radio Frequency Power in plasmas
CountryBelgium
CityGent
Period6/24/096/26/09

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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