Measurement of inner wall limiter SOL widths in KSTAR tokamak
Scrape-off layer (SOL) widths λq are presented from the KSTAR tokamak using fast reciprocating Langmuir probe assembly (FRLPA) measurements at the outboard mid-plane (OMP) and the infra-Red (IR) thermography at inboard limiter tiles in moderately elongated (κ = 1.45 – 1.55) L-mode inner wall-limited...
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| Format: | Article |
| Language: | English |
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Elsevier
2017-08-01
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| Series: | Nuclear Materials and Energy |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2352179116302277 |
| _version_ | 1818339485469900800 |
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| author | J.G. Bak R.A. Pitts H.S. Kim H.H. Lee C. Bin J.W. Juhn S.H. Hong O.E. Garcia R.A. Kube D.C. Seo |
| author_facet | J.G. Bak R.A. Pitts H.S. Kim H.H. Lee C. Bin J.W. Juhn S.H. Hong O.E. Garcia R.A. Kube D.C. Seo |
| author_sort | J.G. Bak |
| collection | DOAJ |
| description | Scrape-off layer (SOL) widths λq are presented from the KSTAR tokamak using fast reciprocating Langmuir probe assembly (FRLPA) measurements at the outboard mid-plane (OMP) and the infra-Red (IR) thermography at inboard limiter tiles in moderately elongated (κ = 1.45 – 1.55) L-mode inner wall-limited (IWL) plasmas under experimental conditions such as BT = 2.0 T, PNBI = 1.4 – 1.5 MW, line averaged densities 2.5 – 5.1 × 1019 m−3 and plasma current Ip = 0.4 − 0.7 MA. There is clear evidence for a double exponential structure in q||(r) from the FRLPA such that, for example at Ip = 0.6 MA, a narrow feature, λq,near (=3.5 mm) is found close to the LFCS, followed by a broader width, λq,main (=57.0 mm). Double exponential profiles (λq,near = 1.5 – 2.8 mm, λq,main = 17.0 – 35.0 mm) can be also observed in the IR heat flux mapped to the OMP throughout the range of Ip investigated. In addition, analysis of SOL turbulence statistics obtained with the FRLPA shows high relative fluctuation levels and positively skewed distributions in electron temperature and ion particle flux across the SOL, with both properties increasing for longer distance from the LCFS, as often previously observed in the tokamaks. Interestingly, the fluctuation character expressed in terms of spectral distributions remains unchanged in passing from the narrow to the broad SOL heat flux channel. Keywords: KSTAR, Inner wall limiter plasma, SOL width, Narrow feature, Electric probe, IR thermal image |
| first_indexed | 2024-12-13T15:27:45Z |
| format | Article |
| id | doaj.art-fe2eb22862fe4867b25c512eae6c5815 |
| institution | Directory Open Access Journal |
| issn | 2352-1791 |
| language | English |
| last_indexed | 2024-12-13T15:27:45Z |
| publishDate | 2017-08-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Nuclear Materials and Energy |
| spelling | doaj.art-fe2eb22862fe4867b25c512eae6c58152022-12-21T23:40:17ZengElsevierNuclear Materials and Energy2352-17912017-08-011212701276Measurement of inner wall limiter SOL widths in KSTAR tokamakJ.G. Bak0R.A. Pitts1H.S. Kim2H.H. Lee3C. Bin4J.W. Juhn5S.H. Hong6O.E. Garcia7R.A. Kube8D.C. Seo9National Fusion Research Institute, Daejeon, Korea; Corresponding author.ITER Organization, Route de Vinon-Verdon, CS90 046, 13067 St. Paul Lez Durance Cedex, FranceNational Fusion Research Institute, Daejeon, KoreaNational Fusion Research Institute, Daejeon, KoreaNational Fusion Research Institute, Daejeon, Korea; Chineses Academy of Science, Institute of Plasma Physics, Hefei, ChinaNational Fusion Research Institute, Daejeon, KoreaNational Fusion Research Institute, Daejeon, KoreaDepartment of Physics and Technology, UiT The Arctic University of Norway, N-9037 Tromsϕ, NorwayDepartment of Physics and Technology, UiT The Arctic University of Norway, N-9037 Tromsϕ, NorwayNational Fusion Research Institute, Daejeon, KoreaScrape-off layer (SOL) widths λq are presented from the KSTAR tokamak using fast reciprocating Langmuir probe assembly (FRLPA) measurements at the outboard mid-plane (OMP) and the infra-Red (IR) thermography at inboard limiter tiles in moderately elongated (κ = 1.45 – 1.55) L-mode inner wall-limited (IWL) plasmas under experimental conditions such as BT = 2.0 T, PNBI = 1.4 – 1.5 MW, line averaged densities 2.5 – 5.1 × 1019 m−3 and plasma current Ip = 0.4 − 0.7 MA. There is clear evidence for a double exponential structure in q||(r) from the FRLPA such that, for example at Ip = 0.6 MA, a narrow feature, λq,near (=3.5 mm) is found close to the LFCS, followed by a broader width, λq,main (=57.0 mm). Double exponential profiles (λq,near = 1.5 – 2.8 mm, λq,main = 17.0 – 35.0 mm) can be also observed in the IR heat flux mapped to the OMP throughout the range of Ip investigated. In addition, analysis of SOL turbulence statistics obtained with the FRLPA shows high relative fluctuation levels and positively skewed distributions in electron temperature and ion particle flux across the SOL, with both properties increasing for longer distance from the LCFS, as often previously observed in the tokamaks. Interestingly, the fluctuation character expressed in terms of spectral distributions remains unchanged in passing from the narrow to the broad SOL heat flux channel. Keywords: KSTAR, Inner wall limiter plasma, SOL width, Narrow feature, Electric probe, IR thermal imagehttp://www.sciencedirect.com/science/article/pii/S2352179116302277 |
| spellingShingle | J.G. Bak R.A. Pitts H.S. Kim H.H. Lee C. Bin J.W. Juhn S.H. Hong O.E. Garcia R.A. Kube D.C. Seo Measurement of inner wall limiter SOL widths in KSTAR tokamak Nuclear Materials and Energy |
| title | Measurement of inner wall limiter SOL widths in KSTAR tokamak |
| title_full | Measurement of inner wall limiter SOL widths in KSTAR tokamak |
| title_fullStr | Measurement of inner wall limiter SOL widths in KSTAR tokamak |
| title_full_unstemmed | Measurement of inner wall limiter SOL widths in KSTAR tokamak |
| title_short | Measurement of inner wall limiter SOL widths in KSTAR tokamak |
| title_sort | measurement of inner wall limiter sol widths in kstar tokamak |
| url | http://www.sciencedirect.com/science/article/pii/S2352179116302277 |
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