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Title: Recent ICRF experiments on HT-7 superconducting tokamak

Abstract

This paper gives an overview of new ICRF techniques developed on HT-7 superconducting tokamak during 1998 campaign, using the present two simple loop antennas, for wall conditioning/boron film deposition of the vessel and start-up of OH discharges: (1) The results show that He-plasma is reliably produced at the standard ICRH frequency (f=22.5 MHz), in a wide range of toroidal field, gas pressure and different RF power level. ICRF cleaning efficiency is about three times higher than that of glow discharge cleaning, this new technique has been used daily during experiments. (2) Start-up experimental results show that RF power was very effective to make the breakdown time less than 2 ms and helpful to assist the plasma start-up when the ICRF power reached 50 kW level. About 10%-20% reduction in the volt-second consumption was achieved according to different condition, evaluated at the beginning of the current flattop. (3) Boronization is carried out by using IBW antenna, the film depth is about 350 nm, and its properties and lifetime are much better than those of GDC method. Comparing with GDC boronization, the residual gas analysis during ICRF boronization showed totally different pattern. For the first time, the repeatable 5 seconds shorts weremore » achieved in HT-7 after ICRF boronization.« less

Authors:
; ; ; ; ; ; ; ; ; ; ;  [1]; ; ; ;  [2]
  1. Institute of Plasma Physics, Academic Sinica, P.O. Box 1126 Hefei, Anlui 230031 (China)
  2. National Institute for Fusion Science, 322-6 Oroshi-Cho, Toki-Shi 509-52 (Japan)
Publication Date:
OSTI Identifier:
21210443
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 485; Journal Issue: 1; Conference: 13. topical conference on radio frequency power in plasmas, Annapolis, MD (United States), 12-14 Apr 1999; Other Information: DOI: 10.1063/1.59726; (c) 1999 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ANTENNAS; BORON; GLOW DISCHARGES; HT-7 TOKAMAK; ICR HEATING; MAGNETIC FIELD CONFIGURATIONS; MHZ RANGE; PHYSICAL VAPOR DEPOSITION; PLASMA; RF SYSTEMS; SUPERCONDUCTING DEVICES; THIN FILMS

Citation Formats

Yang, X. K., Zhao, Y. P., Li, J. G., Li, C. F., Shao, Y. G., Mao, Y. Z., Gu, X. M., Xu, D. Z., Ding, J. Y., Xue, D. Y., Deng, X., Xie, J. K., Watari, T., Kumazawa, R., Seki, T., and Mutoh, T. Recent ICRF experiments on HT-7 superconducting tokamak. United States: N. p., 1999. Web. doi:10.1063/1.59726.
Yang, X. K., Zhao, Y. P., Li, J. G., Li, C. F., Shao, Y. G., Mao, Y. Z., Gu, X. M., Xu, D. Z., Ding, J. Y., Xue, D. Y., Deng, X., Xie, J. K., Watari, T., Kumazawa, R., Seki, T., & Mutoh, T. Recent ICRF experiments on HT-7 superconducting tokamak. United States. doi:10.1063/1.59726.
Yang, X. K., Zhao, Y. P., Li, J. G., Li, C. F., Shao, Y. G., Mao, Y. Z., Gu, X. M., Xu, D. Z., Ding, J. Y., Xue, D. Y., Deng, X., Xie, J. K., Watari, T., Kumazawa, R., Seki, T., and Mutoh, T. Mon . "Recent ICRF experiments on HT-7 superconducting tokamak". United States. doi:10.1063/1.59726.
@article{osti_21210443,
title = {Recent ICRF experiments on HT-7 superconducting tokamak},
author = {Yang, X. K. and Zhao, Y. P. and Li, J. G. and Li, C. F. and Shao, Y. G. and Mao, Y. Z. and Gu, X. M. and Xu, D. Z. and Ding, J. Y. and Xue, D. Y. and Deng, X. and Xie, J. K. and Watari, T. and Kumazawa, R. and Seki, T. and Mutoh, T.},
abstractNote = {This paper gives an overview of new ICRF techniques developed on HT-7 superconducting tokamak during 1998 campaign, using the present two simple loop antennas, for wall conditioning/boron film deposition of the vessel and start-up of OH discharges: (1) The results show that He-plasma is reliably produced at the standard ICRH frequency (f=22.5 MHz), in a wide range of toroidal field, gas pressure and different RF power level. ICRF cleaning efficiency is about three times higher than that of glow discharge cleaning, this new technique has been used daily during experiments. (2) Start-up experimental results show that RF power was very effective to make the breakdown time less than 2 ms and helpful to assist the plasma start-up when the ICRF power reached 50 kW level. About 10%-20% reduction in the volt-second consumption was achieved according to different condition, evaluated at the beginning of the current flattop. (3) Boronization is carried out by using IBW antenna, the film depth is about 350 nm, and its properties and lifetime are much better than those of GDC method. Comparing with GDC boronization, the residual gas analysis during ICRF boronization showed totally different pattern. For the first time, the repeatable 5 seconds shorts were achieved in HT-7 after ICRF boronization.},
doi = {10.1063/1.59726},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 485,
place = {United States},
year = {1999},
month = {9}
}