Investigation of performance enhancement by balanced double-null shaping in KSTAR

Boseong Kim; M.S. Park; Y.H. Lee; S.K. Kim; C.Y. Lee; S.C. Hong; J. Seo; J.G. Lee; S.J. Park; H.-S. Kim; Yong-Su Na

doi:10.1088/1741-4326/acf677

Nuclear Fusion (Jan 2023)

Investigation of performance enhancement by balanced double-null shaping in KSTAR

Boseong Kim,
M.S. Park,
Y.H. Lee,
S.K. Kim,
C.Y. Lee,
S.C. Hong,
J. Seo,
J.G. Lee,
S.J. Park,
H.-S. Kim,
Yong-Su Na

Affiliations

Boseong Kim: ORCiD; Department of Nuclear Engineering, Seoul National University , Seoul, Korea, Republic Of; Korea Institute of Fusion Energy , Daejeon, Korea, Republic Of
M.S. Park: Department of Nuclear Engineering, Seoul National University , Seoul, Korea, Republic Of
Y.H. Lee: ORCiD; Korea Institute of Fusion Energy , Daejeon, Korea, Republic Of
S.K. Kim: ORCiD; Princeton Plasma Physics Laboratory , Princeton, NJ, United States of America
C.Y. Lee: ORCiD; Korea Institute of Fusion Energy , Daejeon, Korea, Republic Of
S.C. Hong: Department of Nuclear Engineering, Seoul National University , Seoul, Korea, Republic Of; Korea Institute of Fusion Energy , Daejeon, Korea, Republic Of
J. Seo: ORCiD; Department of Physics, Chung-Ang University , Seoul, Korea, Republic Of
J.G. Lee: Department of Nuclear Engineering, Seoul National University , Seoul, Korea, Republic Of
S.J. Park: Department of Nuclear Engineering, Seoul National University , Seoul, Korea, Republic Of
H.-S. Kim: ORCiD; Korea Institute of Fusion Energy , Daejeon, Korea, Republic Of
Yong-Su Na: Department of Nuclear Engineering, Seoul National University , Seoul, Korea, Republic Of

DOI: https://doi.org/10.1088/1741-4326/acf677
Journal volume & issue: Vol. 63, no. 12
p. 126013

Abstract

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We report experimental observations on the effect of plasma boundary shaping towards balanced double-null (DN) configuration on the plasma performance in KSTAR. The transition from a single-null to a DN configuration resulted in improved plasma performance, manifested through changes in the pedestal region, decreased density, and core MHD activity variation. Specifically, the DN transition led to a wider and higher pedestal structure, accompanied by grassy edge-localized modes (ELMs) characteristics. The density decrease was a prerequisite for performance enhancement during DN shaping, increasing fast ion confinement. Optimizing the plasma near the core region was associated with the suppression of sawtooth instabilities and the occurrence of fishbone modes during the DN transition. Integrated modeling demonstrated that secondary effects of the DN shaping could increase core thermal energy confinement.

Published in Nuclear Fusion

ISSN: 0029-5515 (Print); 1741-4326 (Online)
Publisher: IOP Publishing
Country of publisher: United Kingdom
LCC subjects: Science: Physics: Nuclear and particle physics. Atomic energy. Radioactivity
Website: https://iopscience.iop.org/journal/0029-5515

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