Energy load on first wall components in high density, small ELM regimes in ASDEX Upgrade
A set of dedicated shots with constant heating power combining NBI (Neutral Beam Injection) and ECRH (Electron Cyclotron Resonance Heating) have been executed at the ASDEX Upgrade (AUG) tokamak using a highly shaped small ELM magnetic geometry in order to investigate the differences on heat loads at...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2023-03-01
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| Series: | Nuclear Materials and Energy |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2352179122002009 |
| _version_ | 1811154435276013568 |
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| author | A. Redl T. Eich N. Vianello P. David |
| author_facet | A. Redl T. Eich N. Vianello P. David |
| author_sort | A. Redl |
| collection | DOAJ |
| description | A set of dedicated shots with constant heating power combining NBI (Neutral Beam Injection) and ECRH (Electron Cyclotron Resonance Heating) have been executed at the ASDEX Upgrade (AUG) tokamak using a highly shaped small ELM magnetic geometry in order to investigate the differences on heat loads at the first wall of AUG by means of the revised cooling water calorimetry. The flattop fuelling has been varied on a shot-to-shot basis while keeping constant all the other parameters, exploring a large range of the density operational space of AUG. Reducing the fuelling rate allows a gradual transition from small ELM regime at high density into a Type-I ELMy H-mode. Additionally, the safety factor q has been increased/decreased by changing Btor, which leads also to variations in the heating scheme. With the lowest flattop fuelling, reaching a Type-I ELMy H-mode, a fraction of ∼ 6% of calorimetrically captured energy loads at the first wall normalized against the entire calorimetrically captured energy has been recorded, whereas in the highest fuelling case, being in a small ELM scenario, the first wall heat loads are increased up to 16%. Considering all cases reveals an almost linear trend between the fraction of energy deposited at the first wall and the turbulence control parameter αt. This observation is consistent with an enhancement of the filamentary activity at higher αt, when the plasma turbulence is dominated by resistive interchange modes at the separatrix. |
| first_indexed | 2024-04-10T04:15:34Z |
| format | Article |
| id | doaj.art-f28e7ef1d66b48f0b0bd3186e6b7a398 |
| institution | Directory Open Access Journal |
| issn | 2352-1791 |
| language | English |
| last_indexed | 2024-04-10T04:15:34Z |
| publishDate | 2023-03-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Nuclear Materials and Energy |
| spelling | doaj.art-f28e7ef1d66b48f0b0bd3186e6b7a3982023-03-12T04:21:18ZengElsevierNuclear Materials and Energy2352-17912023-03-0134101319Energy load on first wall components in high density, small ELM regimes in ASDEX UpgradeA. Redl0T. Eich1N. Vianello2P. David3Department of Economics, Engineering, Society and Business Organization (DEIM), University of Tuscia, Largo dell’Universit‘a snc, 01100 Viterbo, Italy; Corresponding author.Max–Planck-Institute for Plasma Physics, Boltzmannstr.2, 85748 Garching, GermanyConsorzio RFX (CNR, ENEA, INFN, Universitá di Padova, Acciaierie Venete SpA), Corso Stati Uniti 4, 35127 Padova, Italy; Istituto per la Scienza e la Tecnologia dei Plasmi, CNR, Corso Stati Uniti 4, 35127 Padova, ItalyMax–Planck-Institute for Plasma Physics, Boltzmannstr.2, 85748 Garching, GermanyA set of dedicated shots with constant heating power combining NBI (Neutral Beam Injection) and ECRH (Electron Cyclotron Resonance Heating) have been executed at the ASDEX Upgrade (AUG) tokamak using a highly shaped small ELM magnetic geometry in order to investigate the differences on heat loads at the first wall of AUG by means of the revised cooling water calorimetry. The flattop fuelling has been varied on a shot-to-shot basis while keeping constant all the other parameters, exploring a large range of the density operational space of AUG. Reducing the fuelling rate allows a gradual transition from small ELM regime at high density into a Type-I ELMy H-mode. Additionally, the safety factor q has been increased/decreased by changing Btor, which leads also to variations in the heating scheme. With the lowest flattop fuelling, reaching a Type-I ELMy H-mode, a fraction of ∼ 6% of calorimetrically captured energy loads at the first wall normalized against the entire calorimetrically captured energy has been recorded, whereas in the highest fuelling case, being in a small ELM scenario, the first wall heat loads are increased up to 16%. Considering all cases reveals an almost linear trend between the fraction of energy deposited at the first wall and the turbulence control parameter αt. This observation is consistent with an enhancement of the filamentary activity at higher αt, when the plasma turbulence is dominated by resistive interchange modes at the separatrix.http://www.sciencedirect.com/science/article/pii/S2352179122002009ASDEX UpgradeCalorimetric measurementsQCE regimePower Exhaust |
| spellingShingle | A. Redl T. Eich N. Vianello P. David Energy load on first wall components in high density, small ELM regimes in ASDEX Upgrade Nuclear Materials and Energy ASDEX Upgrade Calorimetric measurements QCE regime Power Exhaust |
| title | Energy load on first wall components in high density, small ELM regimes in ASDEX Upgrade |
| title_full | Energy load on first wall components in high density, small ELM regimes in ASDEX Upgrade |
| title_fullStr | Energy load on first wall components in high density, small ELM regimes in ASDEX Upgrade |
| title_full_unstemmed | Energy load on first wall components in high density, small ELM regimes in ASDEX Upgrade |
| title_short | Energy load on first wall components in high density, small ELM regimes in ASDEX Upgrade |
| title_sort | energy load on first wall components in high density small elm regimes in asdex upgrade |
| topic | ASDEX Upgrade Calorimetric measurements QCE regime Power Exhaust |
| url | http://www.sciencedirect.com/science/article/pii/S2352179122002009 |
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