Reduction of core turbulence in I-mode plasmas in Alcator C-Mod
In this paper, we report observations of reduced core (0.40<ρ<0. 95) fluctuations in the edge localized mode (ELM)-free high-confinement regime, I-mode, at Alcator C-Mod (Marmar et al2009 Nucl. Fusion 49 104014). Long wavelength (kθρs<0.5) density fluctuation levels are observed...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Journal article |
| Jezik: | English |
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Institute of Physics Publishing
2014
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| _version_ | 1826264558990262272 |
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| author | White, A Barnes, M Dominguez, A Greenwald, M Howard, N Hubbard, A Hughes, J Mikkelsen, DR Parra, F Reinke, M Sung, C Walk, J Whyte, D |
| author_facet | White, A Barnes, M Dominguez, A Greenwald, M Howard, N Hubbard, A Hughes, J Mikkelsen, DR Parra, F Reinke, M Sung, C Walk, J Whyte, D |
| author_sort | White, A |
| collection | OXFORD |
| description | In this paper, we report observations of reduced core (0.40<ρ<0. 95) fluctuations in the edge localized mode (ELM)-free high-confinement regime, I-mode, at Alcator C-Mod (Marmar et al2009 Nucl. Fusion 49 104014). Long wavelength (kθρs<0.5) density fluctuation levels are observed to decrease from L-mode levels by up to 30% in I-mode, while long wavelength (kθρs<0.3) electron temperature fluctuation levels are observed to decrease by up to 70% in I-mode. This reduction in core turbulence is correlated with the increases in confinement in I-mode compared to L-mode. As the pedestal temperature increases across the L-I transition, core density fluctuations (0.40<ρ<0.95) are reduced prior to the onset of the edge-localized (ρ∼0.99-1.0) weakly coherent mode (WCM) and prior to the reduction of low-frequency (ρ∼0.99-1.0) turbulence in the edge/pedestal region. This result helps add to our understanding of the dynamics of confinement transitions such as I-mode and H-mode, where changes in edge turbulence are more typically observed to occur prior to changes in core turbulence. © 2014 IAEA, Vienna. |
| first_indexed | 2024-03-06T20:09:46Z |
| format | Journal article |
| id | oxford-uuid:2a297565-2918-4525-8483-7095c138dbbf |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T20:09:46Z |
| publishDate | 2014 |
| publisher | Institute of Physics Publishing |
| record_format | dspace |
| spelling | oxford-uuid:2a297565-2918-4525-8483-7095c138dbbf2022-03-26T12:23:26ZReduction of core turbulence in I-mode plasmas in Alcator C-ModJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:2a297565-2918-4525-8483-7095c138dbbfEnglishSymplectic Elements at OxfordInstitute of Physics Publishing2014White, ABarnes, MDominguez, AGreenwald, MHoward, NHubbard, AHughes, JMikkelsen, DRParra, FReinke, MSung, CWalk, JWhyte, DIn this paper, we report observations of reduced core (0.40<ρ<0. 95) fluctuations in the edge localized mode (ELM)-free high-confinement regime, I-mode, at Alcator C-Mod (Marmar et al2009 Nucl. Fusion 49 104014). Long wavelength (kθρs<0.5) density fluctuation levels are observed to decrease from L-mode levels by up to 30% in I-mode, while long wavelength (kθρs<0.3) electron temperature fluctuation levels are observed to decrease by up to 70% in I-mode. This reduction in core turbulence is correlated with the increases in confinement in I-mode compared to L-mode. As the pedestal temperature increases across the L-I transition, core density fluctuations (0.40<ρ<0.95) are reduced prior to the onset of the edge-localized (ρ∼0.99-1.0) weakly coherent mode (WCM) and prior to the reduction of low-frequency (ρ∼0.99-1.0) turbulence in the edge/pedestal region. This result helps add to our understanding of the dynamics of confinement transitions such as I-mode and H-mode, where changes in edge turbulence are more typically observed to occur prior to changes in core turbulence. © 2014 IAEA, Vienna. |
| spellingShingle | White, A Barnes, M Dominguez, A Greenwald, M Howard, N Hubbard, A Hughes, J Mikkelsen, DR Parra, F Reinke, M Sung, C Walk, J Whyte, D Reduction of core turbulence in I-mode plasmas in Alcator C-Mod |
| title | Reduction of core turbulence in I-mode plasmas in Alcator C-Mod |
| title_full | Reduction of core turbulence in I-mode plasmas in Alcator C-Mod |
| title_fullStr | Reduction of core turbulence in I-mode plasmas in Alcator C-Mod |
| title_full_unstemmed | Reduction of core turbulence in I-mode plasmas in Alcator C-Mod |
| title_short | Reduction of core turbulence in I-mode plasmas in Alcator C-Mod |
| title_sort | reduction of core turbulence in i mode plasmas in alcator c mod |
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