Experimental characteristics of lost fast negative ions on EAST tokamak
It is the first time that fast negative-ion loss signals are observed by Fast-ion Loss Detector (FILD) and analyzed in EAST neutral beam injection experiment. Velocity-space distributions of lost fast negative and positive ions reconstructed by the FILDSIM code are basically consistent. Orbit analys...
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IOP Publishing
2025-01-01
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| Series: | Nuclear Fusion |
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| Online Access: | https://doi.org/10.1088/1741-4326/adb7ee |
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| author | Z.X. Zhang J. Huang J.F. Chang C.R. Wu J. Galdon-Quiroga A. Snicker M. Isobe K. Ogawa K.Y. He S.S. Wang Y.X. Sun X.H. Wang the EAST Team |
| author_facet | Z.X. Zhang J. Huang J.F. Chang C.R. Wu J. Galdon-Quiroga A. Snicker M. Isobe K. Ogawa K.Y. He S.S. Wang Y.X. Sun X.H. Wang the EAST Team |
| author_sort | Z.X. Zhang |
| collection | DOAJ |
| description | It is the first time that fast negative-ion loss signals are observed by Fast-ion Loss Detector (FILD) and analyzed in EAST neutral beam injection experiment. Velocity-space distributions of lost fast negative and positive ions reconstructed by the FILDSIM code are basically consistent. Orbit analysis backtracked by the ASCOT code shows that the fast negative ions are generated at the low-field side (LFS) scrape-off layer, whereas the fast positive ions are generated near the last closed flux surface (LCFS) at both the high- and LFSs. The existence of fast negative-ion loss indirectly suggests a very high neutral particle density near both the main limiter and antenna limiter. The differing birth locations of fast positive and negative ions result in distinct loss behaviors during ELM H-mode and n = 3 rotating RMP experiments. The asymmetry of neutral particle density in tokamak suggest that previous studies may have underestimated the fraction of charge exchange (CX) losses due to the assumption of a uniform neutral particle density outside the LCFS. Therefore, simulations evaluating the CX loss fraction in the future should account for a three-dimensional distribution of neutral particle density, including local gas puffing and the neutral particle density around various limiters. |
| format | Article |
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| institution | DOAJ |
| issn | 0029-5515 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | Nuclear Fusion |
| spelling | doaj-art-58de3d7dd1ab4dbe98ada90019f0b99c2025-08-20T02:55:35ZengIOP PublishingNuclear Fusion0029-55152025-01-0165404600110.1088/1741-4326/adb7eeExperimental characteristics of lost fast negative ions on EAST tokamakZ.X. Zhang0https://orcid.org/0009-0004-0193-0549J. Huang1https://orcid.org/0000-0001-5662-809XJ.F. Chang2C.R. Wu3J. Galdon-Quiroga4https://orcid.org/0000-0002-7415-1894A. Snicker5M. Isobe6K. Ogawa7https://orcid.org/0000-0003-4555-1837K.Y. He8S.S. Wang9Y.X. Sun10X.H. Wang11https://orcid.org/0000-0001-8191-9606the EAST Team12Institute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, ChinaShiyan Key Laboratory of Quantum Information and Precision Optics , School of Mathematics, Physics and Optoelectronic Engineering, Hubei University of Automotive Technology, Shiyan 442002, ChinaDepartment of Atomic, Molecular and Nuclear Physics, University of Seville , E-41012 Seville, SpainDepartment of Applied Physics, Aalto University , PO Box 11100, Helsinki FI-00076 AALTO, Finland; VTT Technical Research Centre of Finland Ltd , Kivimiehentie 3, Espoo, FinlandNational Institute for Fusion Science , National Institutes of Natural Sciences, Toki 509-5292, Japan; SOKENDAI (The Graduate University for Advanced Studies) , Toki 509-5292, JapanNational Institute for Fusion Science , National Institutes of Natural Sciences, Toki 509-5292, Japan; SOKENDAI (The Graduate University for Advanced Studies) , Toki 509-5292, JapanInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, ChinaQingdao Sifang SRI Intellectual Technology Co. , Ltd, Qingdao 266031, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, China; University of Science and Technology of China , Hefei 230026, ChinaInstitute of Plasma Physics , Hefei Institutes of Physical Science Chinese Academy of Sciences, Hefei 230031, ChinaIt is the first time that fast negative-ion loss signals are observed by Fast-ion Loss Detector (FILD) and analyzed in EAST neutral beam injection experiment. Velocity-space distributions of lost fast negative and positive ions reconstructed by the FILDSIM code are basically consistent. Orbit analysis backtracked by the ASCOT code shows that the fast negative ions are generated at the low-field side (LFS) scrape-off layer, whereas the fast positive ions are generated near the last closed flux surface (LCFS) at both the high- and LFSs. The existence of fast negative-ion loss indirectly suggests a very high neutral particle density near both the main limiter and antenna limiter. The differing birth locations of fast positive and negative ions result in distinct loss behaviors during ELM H-mode and n = 3 rotating RMP experiments. The asymmetry of neutral particle density in tokamak suggest that previous studies may have underestimated the fraction of charge exchange (CX) losses due to the assumption of a uniform neutral particle density outside the LCFS. Therefore, simulations evaluating the CX loss fraction in the future should account for a three-dimensional distribution of neutral particle density, including local gas puffing and the neutral particle density around various limiters.https://doi.org/10.1088/1741-4326/adb7eefast negative-ion lossEAST tokamakFILDvelocity-space distribution |
| spellingShingle | Z.X. Zhang J. Huang J.F. Chang C.R. Wu J. Galdon-Quiroga A. Snicker M. Isobe K. Ogawa K.Y. He S.S. Wang Y.X. Sun X.H. Wang the EAST Team Experimental characteristics of lost fast negative ions on EAST tokamak Nuclear Fusion fast negative-ion loss EAST tokamak FILD velocity-space distribution |
| title | Experimental characteristics of lost fast negative ions on EAST tokamak |
| title_full | Experimental characteristics of lost fast negative ions on EAST tokamak |
| title_fullStr | Experimental characteristics of lost fast negative ions on EAST tokamak |
| title_full_unstemmed | Experimental characteristics of lost fast negative ions on EAST tokamak |
| title_short | Experimental characteristics of lost fast negative ions on EAST tokamak |
| title_sort | experimental characteristics of lost fast negative ions on east tokamak |
| topic | fast negative-ion loss EAST tokamak FILD velocity-space distribution |
| url | https://doi.org/10.1088/1741-4326/adb7ee |
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