A scaling law of the neutral penetration length and Balmer-α wing shape in high-temperature plasmas
Hydrogen atoms penetrating deep inside high-temperature magnetically confined plasmas by repetitive charge-exchange collisions result in a particle source of the plasma, which affects the plasma transport significantly. In this paper, we present an approximate solution of the fluid equations for neu...
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| Format: | Article |
| Language: | English |
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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/add358 |
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| author | Keisuke Fujii Masahiro Hasuo Motoshi Goto Jeremy D. Lore |
| author_facet | Keisuke Fujii Masahiro Hasuo Motoshi Goto Jeremy D. Lore |
| author_sort | Keisuke Fujii |
| collection | DOAJ |
| description | Hydrogen atoms penetrating deep inside high-temperature magnetically confined plasmas by repetitive charge-exchange collisions result in a particle source of the plasma, which affects the plasma transport significantly. In this paper, we present an approximate solution of the fluid equations for neutral transport and an analytical representation of the neutral penetration length, in a simplified plasma geometry. This analysis predicts a power-law decay in the Balmer- α line wings which reflects the velocity distribution of the neutral atoms, with the power-law exponent analytically represented as well. These scaling laws are compared with a simple Monte–Carlo simulation and spectroscopic observations of Large Helical Device plasmas. Since the Balmer- α line wings are experimentally accessible, our formulation opens the possibility to quickly estimate the neutral penetration length from spectroscopic observations. |
| format | Article |
| id | doaj-art-a8a1f40566c945a79a334e2d70a74be5 |
| institution | DOAJ |
| issn | 0029-5515 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | Nuclear Fusion |
| spelling | doaj-art-a8a1f40566c945a79a334e2d70a74be52025-08-20T02:59:07ZengIOP PublishingNuclear Fusion0029-55152025-01-0165606601410.1088/1741-4326/add358A scaling law of the neutral penetration length and Balmer-α wing shape in high-temperature plasmasKeisuke Fujii0https://orcid.org/0000-0003-0390-9984Masahiro Hasuo1Motoshi Goto2https://orcid.org/0000-0002-9160-682XJeremy D. Lore3https://orcid.org/0000-0002-9192-465XFusion Energy Division, Oak Ridge National Laboratory , Oak Ridge, TN 37831-6305, United States of AmericaDepartment of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University , Kyoto 615-8540, JapanNational Institute for Fusion Science , Toki, Gifu 5909-5292, Japan; Department of Fusion Science, The Graduate University for Advanced Studies , SOKENDAI, Toki 509-5292, JapanFusion Energy Division, Oak Ridge National Laboratory , Oak Ridge, TN 37831-6305, United States of AmericaHydrogen atoms penetrating deep inside high-temperature magnetically confined plasmas by repetitive charge-exchange collisions result in a particle source of the plasma, which affects the plasma transport significantly. In this paper, we present an approximate solution of the fluid equations for neutral transport and an analytical representation of the neutral penetration length, in a simplified plasma geometry. This analysis predicts a power-law decay in the Balmer- α line wings which reflects the velocity distribution of the neutral atoms, with the power-law exponent analytically represented as well. These scaling laws are compared with a simple Monte–Carlo simulation and spectroscopic observations of Large Helical Device plasmas. Since the Balmer- α line wings are experimentally accessible, our formulation opens the possibility to quickly estimate the neutral penetration length from spectroscopic observations.https://doi.org/10.1088/1741-4326/add358particle sourcespectroscopyneutral opacity |
| spellingShingle | Keisuke Fujii Masahiro Hasuo Motoshi Goto Jeremy D. Lore A scaling law of the neutral penetration length and Balmer-α wing shape in high-temperature plasmas Nuclear Fusion particle source spectroscopy neutral opacity |
| title | A scaling law of the neutral penetration length and Balmer-α wing shape in high-temperature plasmas |
| title_full | A scaling law of the neutral penetration length and Balmer-α wing shape in high-temperature plasmas |
| title_fullStr | A scaling law of the neutral penetration length and Balmer-α wing shape in high-temperature plasmas |
| title_full_unstemmed | A scaling law of the neutral penetration length and Balmer-α wing shape in high-temperature plasmas |
| title_short | A scaling law of the neutral penetration length and Balmer-α wing shape in high-temperature plasmas |
| title_sort | scaling law of the neutral penetration length and balmer α wing shape in high temperature plasmas |
| topic | particle source spectroscopy neutral opacity |
| url | https://doi.org/10.1088/1741-4326/add358 |
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