Experimental signatures of critically balanced turbulence in MAST.
Beam emission spectroscopy (BES) measurements of ion-scale density fluctuations in the MAST tokamak are used to show that the turbulence correlation time, the drift time associated with ion temperature or density gradients, the particle (ion) streaming time along the magnetic field, and the magnetic...
| Главные авторы: | , , , , , , , , , |
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| Формат: | Journal article |
| Язык: | English |
| Опубликовано: |
2013
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| _version_ | 1826292849351589888 |
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| author | Ghim, Y Schekochihin, A Field, A Abel, I Barnes, M Colyer, G Cowley, S Parra, F Dunai, D Zoletnik, S |
| author_facet | Ghim, Y Schekochihin, A Field, A Abel, I Barnes, M Colyer, G Cowley, S Parra, F Dunai, D Zoletnik, S |
| author_sort | Ghim, Y |
| collection | OXFORD |
| description | Beam emission spectroscopy (BES) measurements of ion-scale density fluctuations in the MAST tokamak are used to show that the turbulence correlation time, the drift time associated with ion temperature or density gradients, the particle (ion) streaming time along the magnetic field, and the magnetic drift time are consistently comparable, suggesting a "critically balanced" turbulence determined by the local equilibrium. The resulting scalings of the poloidal and radial correlation lengths are derived and tested. The nonlinear time inferred from the density fluctuations is longer than the other times; its ratio to the correlation time scales as ν(*i)(-0.8 ± 0.1), where ν(*i) = ion collision rate/streaming rate. This is consistent with turbulent decorrelation being controlled by a zonal component, invisible to the BES, with an amplitude exceeding those of the drift waves by ∼ ν(*i)(-0.8). |
| first_indexed | 2024-03-07T03:21:02Z |
| format | Journal article |
| id | oxford-uuid:b76d2a49-0a91-47e7-b3aa-327d85e18fa3 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T03:21:02Z |
| publishDate | 2013 |
| record_format | dspace |
| spelling | oxford-uuid:b76d2a49-0a91-47e7-b3aa-327d85e18fa32022-03-27T04:48:32ZExperimental signatures of critically balanced turbulence in MAST.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:b76d2a49-0a91-47e7-b3aa-327d85e18fa3EnglishSymplectic Elements at Oxford2013Ghim, YSchekochihin, AField, AAbel, IBarnes, MColyer, GCowley, SParra, FDunai, DZoletnik, SBeam emission spectroscopy (BES) measurements of ion-scale density fluctuations in the MAST tokamak are used to show that the turbulence correlation time, the drift time associated with ion temperature or density gradients, the particle (ion) streaming time along the magnetic field, and the magnetic drift time are consistently comparable, suggesting a "critically balanced" turbulence determined by the local equilibrium. The resulting scalings of the poloidal and radial correlation lengths are derived and tested. The nonlinear time inferred from the density fluctuations is longer than the other times; its ratio to the correlation time scales as ν(*i)(-0.8 ± 0.1), where ν(*i) = ion collision rate/streaming rate. This is consistent with turbulent decorrelation being controlled by a zonal component, invisible to the BES, with an amplitude exceeding those of the drift waves by ∼ ν(*i)(-0.8). |
| spellingShingle | Ghim, Y Schekochihin, A Field, A Abel, I Barnes, M Colyer, G Cowley, S Parra, F Dunai, D Zoletnik, S Experimental signatures of critically balanced turbulence in MAST. |
| title | Experimental signatures of critically balanced turbulence in MAST. |
| title_full | Experimental signatures of critically balanced turbulence in MAST. |
| title_fullStr | Experimental signatures of critically balanced turbulence in MAST. |
| title_full_unstemmed | Experimental signatures of critically balanced turbulence in MAST. |
| title_short | Experimental signatures of critically balanced turbulence in MAST. |
| title_sort | experimental signatures of critically balanced turbulence in mast |
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