Electron temperature fluctuation levels of the quasi-coherent mode across the plasma radius
EDA H-mode is an ELM-free regime in which the edge quasi-coherent mode (QCM) replaces the ELMs. The estimated location of the quasi-coherent mode is in a partly optically thin region of steep gradients localized between ρpol = 0.96 -1. Relative fluctuations of radiation temperature between 15 and 80...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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EDP Sciences
2023-01-01
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| Series: | EPJ Web of Conferences |
| Online Access: | https://www.epj-conferences.org/articles/epjconf/pdf/2023/03/epjconf_ec212023_03003.pdf |
| _version_ | 1797894067137282048 |
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| author | Vanovac Branka Stober Jörg Wolfrum Elisabeth Willensdorfer Matthias Gil Luís Faitsch Michael Bielajew Rachel Yoo Christian Conway Garrard Denk Severin McDermott Rachael White Anne |
| author_facet | Vanovac Branka Stober Jörg Wolfrum Elisabeth Willensdorfer Matthias Gil Luís Faitsch Michael Bielajew Rachel Yoo Christian Conway Garrard Denk Severin McDermott Rachael White Anne |
| author_sort | Vanovac Branka |
| collection | DOAJ |
| description | EDA H-mode is an ELM-free regime in which the edge quasi-coherent mode (QCM) replaces the ELMs. The estimated location of the quasi-coherent mode is in a partly optically thin region of steep gradients localized between ρpol = 0.96 -1. Relative fluctuations of radiation temperature between 15 and 80 kHz are about 7% with significant density contribution. In the electron cyclotron emission (ECE) channels with resonances in the plasma core, a mode with the same frequency as the quasi-coherent mode is measured. The peak amplitude of both core and edge modes matches the strongest electron temperature gradient in the core and the edge, respectively. The ECE core and edge signals are out of phase. The radiation transport forward model (ECRad) shows that the refraction explains the phase relation between the edge and the core ECE channels. The phase correlates with the sign of the core Te. The amplitude of the fluctuations in the core decreases with decreasing gradients, which is the trend seen in the experiment. The amplitude ratio of the core and edge fluctuation is a factor of five in the experiment; this ratio remains a factor of a hundred in the modeling. |
| first_indexed | 2024-04-10T07:02:56Z |
| format | Article |
| id | doaj.art-8bd31574b95f40f8a7ef51c7ee70bc00 |
| institution | Directory Open Access Journal |
| issn | 2100-014X |
| language | English |
| last_indexed | 2024-04-10T07:02:56Z |
| publishDate | 2023-01-01 |
| publisher | EDP Sciences |
| record_format | Article |
| series | EPJ Web of Conferences |
| spelling | doaj.art-8bd31574b95f40f8a7ef51c7ee70bc002023-02-27T15:17:49ZengEDP SciencesEPJ Web of Conferences2100-014X2023-01-012770300310.1051/epjconf/202327703003epjconf_ec212023_03003Electron temperature fluctuation levels of the quasi-coherent mode across the plasma radiusVanovac Branka0Stober Jörg1Wolfrum Elisabeth2Willensdorfer Matthias3Gil Luís4Faitsch Michael5Bielajew Rachel6Yoo Christian7Conway Garrard8Denk Severin9McDermott Rachael10White Anne11Massachusetts Institute of Technology, Plasma Science and Fusion CenterMax Plank Institute for Plasma PhysicsMax Plank Institute for Plasma PhysicsMax Plank Institute for Plasma PhysicsInstituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de LisboaMax Plank Institute for Plasma PhysicsMassachusetts Institute of Technology, Plasma Science and Fusion CenterMassachusetts Institute of Technology, Plasma Science and Fusion CenterMax Plank Institute for Plasma PhysicsMassachusetts Institute of Technology, Plasma Science and Fusion CenterMax Plank Institute for Plasma PhysicsMassachusetts Institute of Technology, Plasma Science and Fusion CenterEDA H-mode is an ELM-free regime in which the edge quasi-coherent mode (QCM) replaces the ELMs. The estimated location of the quasi-coherent mode is in a partly optically thin region of steep gradients localized between ρpol = 0.96 -1. Relative fluctuations of radiation temperature between 15 and 80 kHz are about 7% with significant density contribution. In the electron cyclotron emission (ECE) channels with resonances in the plasma core, a mode with the same frequency as the quasi-coherent mode is measured. The peak amplitude of both core and edge modes matches the strongest electron temperature gradient in the core and the edge, respectively. The ECE core and edge signals are out of phase. The radiation transport forward model (ECRad) shows that the refraction explains the phase relation between the edge and the core ECE channels. The phase correlates with the sign of the core Te. The amplitude of the fluctuations in the core decreases with decreasing gradients, which is the trend seen in the experiment. The amplitude ratio of the core and edge fluctuation is a factor of five in the experiment; this ratio remains a factor of a hundred in the modeling.https://www.epj-conferences.org/articles/epjconf/pdf/2023/03/epjconf_ec212023_03003.pdf |
| spellingShingle | Vanovac Branka Stober Jörg Wolfrum Elisabeth Willensdorfer Matthias Gil Luís Faitsch Michael Bielajew Rachel Yoo Christian Conway Garrard Denk Severin McDermott Rachael White Anne Electron temperature fluctuation levels of the quasi-coherent mode across the plasma radius EPJ Web of Conferences |
| title | Electron temperature fluctuation levels of the quasi-coherent mode across the plasma radius |
| title_full | Electron temperature fluctuation levels of the quasi-coherent mode across the plasma radius |
| title_fullStr | Electron temperature fluctuation levels of the quasi-coherent mode across the plasma radius |
| title_full_unstemmed | Electron temperature fluctuation levels of the quasi-coherent mode across the plasma radius |
| title_short | Electron temperature fluctuation levels of the quasi-coherent mode across the plasma radius |
| title_sort | electron temperature fluctuation levels of the quasi coherent mode across the plasma radius |
| url | https://www.epj-conferences.org/articles/epjconf/pdf/2023/03/epjconf_ec212023_03003.pdf |
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