ELM elimination with Li powder injection in east discharges using the tungsten upper divertor

R. Maingi, J. S. Hu, Z. Sun, K. Tritz, G. Z. Zuo, W. Xu, M. Huang, X. C. Meng, J. M. Canik, A. Diallo, R. Lunsford, D. K. Mansfield, T. H. Osborne, X. Z. Gong, Y. F. Wang, Y. Y. Li

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

We report the first successful use of lithium (Li) to eliminate edge-localized modes (ELMs) with tungsten divertor plasma-facing components in the EAST device. Li powder injected into the scrape-off layer of the tungsten upper divertor successfully eliminated ELMs for 3-5 s in EAST. The ELM elimination became progressively more effective in consecutive discharges at constant lithium delivery rates, and the divertor Da baseline emission was reduced, both signatures of improved wall conditioning. A modest decrease in stored energy and normalized energy confinement was also observed, but the confinement relative to H98 remained well above 1, extending the previous ELM elimination results via Li injection into the lower carbon divertor in EAST (Hu et al 2015 Phys. Rev. Lett. 114 055001). These results can be compared with recent observations with lithium pellets in ASDEX-Upgrade that failed to mitigate ELMs (Lang et al 2017 Nucl. Fusion 57 016030), highlighting one comparative advantage of continuous powder injection for real-Time ELM elimination.

Original languageEnglish
Article number024003
JournalNuclear Fusion
Volume58
Issue number2
DOIs
StatePublished - Feb 2018

Funding

This research was supported in part by the U.S. Dept. of Energy Contracts DE-AC02-09CH11466, DE-FG02-09ER55012 and DE-FC02-04ER54698, and partly by the National Key Research and Development Program of China under Contract No. 2017YFA0402500, the National Nature Science Foundation of China under Contract No.11625524, No.11605246, No.11405210 and National Magnetic confinement Fusion Science Program of China under Contract No. 2013GB114004. The digital data for this paper can be found at: http://arks.princeton.edu/ark:/88435/dsp01wp988n475 We gratefully acknowledge the contributions from the EAST technical staff. Notice: This manuscript is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, and has been authored by Princeton University under Contract Number DE-AC02-09CH11466 with the U.S. Department of Energy. The publisher, by accepting the article for publication acknowledges, that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.

Keywords

  • Edge localized modes
  • Edge stability
  • Lithium seeding
  • Plasma wall interactions

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