Addressing the impact of Lyman opacity in inference of divertor plasma conditions with 2D spectroscopic camera analysis of Balmer emission during detachment in JET L-mode plasmas
The impact of re-absorption of the deuterium Lyman series emission was addressed in inferring divertor plasma conditions from Balmer series emission with 2D spectroscopic camera analysis during detachment in JET L-mode plasmas. The previously presented methodology was amended by modifying the standa...
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Elsevier
2025-03-01
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| Series: | Nuclear Materials and Energy |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2352179125000201 |
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| author | J. Karhunen B. Lomanowski S. Aleiferis P. Carvalho M. Groth A. Holm K.D. Lawson A.G. Meigs A. Shaw V. Solokha |
| author_facet | J. Karhunen B. Lomanowski S. Aleiferis P. Carvalho M. Groth A. Holm K.D. Lawson A.G. Meigs A. Shaw V. Solokha |
| author_sort | J. Karhunen |
| collection | DOAJ |
| description | The impact of re-absorption of the deuterium Lyman series emission was addressed in inferring divertor plasma conditions from Balmer series emission with 2D spectroscopic camera analysis during detachment in JET L-mode plasmas. The previously presented methodology was amended by modifying the standard photon emission coefficients and ionization and recombination rate coefficients of the ADAS database to consider the re-population of excited states due to Lyman opacity. This resulted in the estimate for the atomic density near the outer strike point to decrease by up to 75% at the onset of detachment at strike point temperatures of Te,osp≈ 1.0–3.0 eV with respect to the strongly overestimated previously obtained values, whereas the estimated electron temperature and density were unaffected by the opacity correction within the scatter of the data and only a moderate reduction by up to 20% was observed in the estimate for the molecularly induced fraction of the Balmer emission. No noticeable change was seen in the ionization rate, calculated from the estimated outer strike point conditions, due to the decrease in the atomic density estimate compensating for the increased values of the opacity-corrected ADAS rate coefficients for ionization. In detached conditions at Te,osp≈ 0.5–1.0 eV, 25%–35% lower recombination rates were provided by the opacity-corrected model. The observed effects on the experimental analysis were supported by a corresponding synthetic analysis based on EDGE2D-EIRENE simulations. |
| format | Article |
| id | doaj-art-9a0dc89e657d4a8d842dabd035a9b6c6 |
| institution | DOAJ |
| issn | 2352-1791 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Nuclear Materials and Energy |
| spelling | doaj-art-9a0dc89e657d4a8d842dabd035a9b6c62025-08-20T02:47:39ZengElsevierNuclear Materials and Energy2352-17912025-03-014210188010.1016/j.nme.2025.101880Addressing the impact of Lyman opacity in inference of divertor plasma conditions with 2D spectroscopic camera analysis of Balmer emission during detachment in JET L-mode plasmasJ. Karhunen0B. Lomanowski1S. Aleiferis2P. Carvalho3M. Groth4A. Holm5K.D. Lawson6A.G. Meigs7A. Shaw8V. Solokha9VTT Technical Research Centre of Finland, Espoo, 02044, Finland; Corresponding author.Oak Ridge National Laboratory, Oak Ridge, TN 37831, USAUKAEA, Culham Science Centre, Abingdon, OX14 3DB, UKUKAEA, Culham Science Centre, Abingdon, OX14 3DB, UKAalto University, Department of Applied Physics, Espoo, 02150, FinlandLawrence Livermore National Laboratory, Livermore, CA 94550, USAUKAEA, Culham Science Centre, Abingdon, OX14 3DB, UKUKAEA, Culham Science Centre, Abingdon, OX14 3DB, UKUKAEA, Culham Science Centre, Abingdon, OX14 3DB, UKAalto University, Department of Applied Physics, Espoo, 02150, FinlandThe impact of re-absorption of the deuterium Lyman series emission was addressed in inferring divertor plasma conditions from Balmer series emission with 2D spectroscopic camera analysis during detachment in JET L-mode plasmas. The previously presented methodology was amended by modifying the standard photon emission coefficients and ionization and recombination rate coefficients of the ADAS database to consider the re-population of excited states due to Lyman opacity. This resulted in the estimate for the atomic density near the outer strike point to decrease by up to 75% at the onset of detachment at strike point temperatures of Te,osp≈ 1.0–3.0 eV with respect to the strongly overestimated previously obtained values, whereas the estimated electron temperature and density were unaffected by the opacity correction within the scatter of the data and only a moderate reduction by up to 20% was observed in the estimate for the molecularly induced fraction of the Balmer emission. No noticeable change was seen in the ionization rate, calculated from the estimated outer strike point conditions, due to the decrease in the atomic density estimate compensating for the increased values of the opacity-corrected ADAS rate coefficients for ionization. In detached conditions at Te,osp≈ 0.5–1.0 eV, 25%–35% lower recombination rates were provided by the opacity-corrected model. The observed effects on the experimental analysis were supported by a corresponding synthetic analysis based on EDGE2D-EIRENE simulations.http://www.sciencedirect.com/science/article/pii/S2352179125000201FusionDivertor detachmentBalmer emissionLyman opacity |
| spellingShingle | J. Karhunen B. Lomanowski S. Aleiferis P. Carvalho M. Groth A. Holm K.D. Lawson A.G. Meigs A. Shaw V. Solokha Addressing the impact of Lyman opacity in inference of divertor plasma conditions with 2D spectroscopic camera analysis of Balmer emission during detachment in JET L-mode plasmas Nuclear Materials and Energy Fusion Divertor detachment Balmer emission Lyman opacity |
| title | Addressing the impact of Lyman opacity in inference of divertor plasma conditions with 2D spectroscopic camera analysis of Balmer emission during detachment in JET L-mode plasmas |
| title_full | Addressing the impact of Lyman opacity in inference of divertor plasma conditions with 2D spectroscopic camera analysis of Balmer emission during detachment in JET L-mode plasmas |
| title_fullStr | Addressing the impact of Lyman opacity in inference of divertor plasma conditions with 2D spectroscopic camera analysis of Balmer emission during detachment in JET L-mode plasmas |
| title_full_unstemmed | Addressing the impact of Lyman opacity in inference of divertor plasma conditions with 2D spectroscopic camera analysis of Balmer emission during detachment in JET L-mode plasmas |
| title_short | Addressing the impact of Lyman opacity in inference of divertor plasma conditions with 2D spectroscopic camera analysis of Balmer emission during detachment in JET L-mode plasmas |
| title_sort | addressing the impact of lyman opacity in inference of divertor plasma conditions with 2d spectroscopic camera analysis of balmer emission during detachment in jet l mode plasmas |
| topic | Fusion Divertor detachment Balmer emission Lyman opacity |
| url | http://www.sciencedirect.com/science/article/pii/S2352179125000201 |
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