Mean flows and blob velocities in scrape-off layer (SOLT) simulations of an L-mode discharge on Alcator C-Mod
Two-dimensional scrape-off layer turbulence (SOLT) code simulations are compared with an L-mode discharge on the Alcator C-Mod tokamak [Greenwald et al., Phys. Plasmas 21, 110501 (2014)]. Density and temperature profiles for the simulations were obtained by smoothly fitting Thomson scattering and mi...
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American Institute of Physics (AIP)
2018
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| Online Access: | http://hdl.handle.net/1721.1/113071 https://orcid.org/0000-0002-7841-9261 |
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| author | Russell, D. A. Myra, J. R. D'Ippolito, D. A. Zweben, S. J. Labombard, Brian Hughes Jr, Jerry Terry, James L |
| author2 | Massachusetts Institute of Technology. Plasma Science and Fusion Center |
| author_facet | Massachusetts Institute of Technology. Plasma Science and Fusion Center Russell, D. A. Myra, J. R. D'Ippolito, D. A. Zweben, S. J. Labombard, Brian Hughes Jr, Jerry Terry, James L |
| author_sort | Russell, D. A. |
| collection | MIT |
| description | Two-dimensional scrape-off layer turbulence (SOLT) code simulations are compared with an L-mode discharge on the Alcator C-Mod tokamak [Greenwald et al., Phys. Plasmas 21, 110501 (2014)]. Density and temperature profiles for the simulations were obtained by smoothly fitting Thomson scattering and mirror Langmuir probe (MLP) data from the shot. Simulations differing in turbulence intensity were obtained by varying a dissipation parameter. Mean flow profiles and density fluctuation amplitudes are consistent with those measured by MLP in the experiment and with a Fourier space diagnostic designed to measure poloidal phase velocity. Blob velocities in the simulations were determined from the correlation function for density fluctuations, as in the analysis of gas-puff-imaging (GPI) blobs in the experiment. In the simulations, it was found that larger blobs moved poloidally with the E × B flow velocity, v E , in the near-SOL, while smaller fluctuations moved with the group velocity of the dominant linear (interchange) mode, v[subscript E] + 1/2 v[subscript di] , where v [subscript di] is the ion diamagnetic drift velocity. Comparisons are made with the measured GPI correlation velocity for the discharge. The saturation mechanisms operative in the simulation of the discharge are also discussed. It is found that neither sheared flow nor pressure gradient modification can be excluded as saturation mechanisms. |
| first_indexed | 2024-09-23T14:20:28Z |
| format | Article |
| id | mit-1721.1/113071 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T14:20:28Z |
| publishDate | 2018 |
| publisher | American Institute of Physics (AIP) |
| record_format | dspace |
| spelling | mit-1721.1/1130712022-10-01T20:42:55Z Mean flows and blob velocities in scrape-off layer (SOLT) simulations of an L-mode discharge on Alcator C-Mod Russell, D. A. Myra, J. R. D'Ippolito, D. A. Zweben, S. J. Labombard, Brian Hughes Jr, Jerry Terry, James L Massachusetts Institute of Technology. Plasma Science and Fusion Center Labombard, Brian Hughes Jr, Jerry Terry, James L Two-dimensional scrape-off layer turbulence (SOLT) code simulations are compared with an L-mode discharge on the Alcator C-Mod tokamak [Greenwald et al., Phys. Plasmas 21, 110501 (2014)]. Density and temperature profiles for the simulations were obtained by smoothly fitting Thomson scattering and mirror Langmuir probe (MLP) data from the shot. Simulations differing in turbulence intensity were obtained by varying a dissipation parameter. Mean flow profiles and density fluctuation amplitudes are consistent with those measured by MLP in the experiment and with a Fourier space diagnostic designed to measure poloidal phase velocity. Blob velocities in the simulations were determined from the correlation function for density fluctuations, as in the analysis of gas-puff-imaging (GPI) blobs in the experiment. In the simulations, it was found that larger blobs moved poloidally with the E × B flow velocity, v E , in the near-SOL, while smaller fluctuations moved with the group velocity of the dominant linear (interchange) mode, v[subscript E] + 1/2 v[subscript di] , where v [subscript di] is the ion diamagnetic drift velocity. Comparisons are made with the measured GPI correlation velocity for the discharge. The saturation mechanisms operative in the simulation of the discharge are also discussed. It is found that neither sheared flow nor pressure gradient modification can be excluded as saturation mechanisms. United States. Department of Energy. Office of Fusion Energy Sciences (Grant DE-FG02-97ER54392) United States. Department of Energy. Office of Fusion Energy Sciences (Agreement DE-FC02-99ER54512) United States. Department of Energy. Office of Fusion Energy Sciences (Contract DE-AC02-09CH11466) 2018-01-11T20:52:25Z 2018-01-11T20:52:25Z 2016-06 2016-03 2018-01-11T15:50:17Z Article http://purl.org/eprint/type/JournalArticle 1070-664X 1089-7674 http://hdl.handle.net/1721.1/113071 Russell, D. A. et al. “Mean Flows and Blob Velocities in Scrape-Off Layer (SOLT) Simulations of an L-Mode Discharge on Alcator C-Mod.” Physics of Plasmas 23, 6 (June 2016): 062305 © 2016 Author(s) https://orcid.org/0000-0002-7841-9261 http://dx.doi.org/10.1063/1.4953419 Physics of Plasmas Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Institute of Physics (AIP) MIT Plasma Science & Fusion Center |
| spellingShingle | Russell, D. A. Myra, J. R. D'Ippolito, D. A. Zweben, S. J. Labombard, Brian Hughes Jr, Jerry Terry, James L Mean flows and blob velocities in scrape-off layer (SOLT) simulations of an L-mode discharge on Alcator C-Mod |
| title | Mean flows and blob velocities in scrape-off layer (SOLT) simulations of an L-mode discharge on Alcator C-Mod |
| title_full | Mean flows and blob velocities in scrape-off layer (SOLT) simulations of an L-mode discharge on Alcator C-Mod |
| title_fullStr | Mean flows and blob velocities in scrape-off layer (SOLT) simulations of an L-mode discharge on Alcator C-Mod |
| title_full_unstemmed | Mean flows and blob velocities in scrape-off layer (SOLT) simulations of an L-mode discharge on Alcator C-Mod |
| title_short | Mean flows and blob velocities in scrape-off layer (SOLT) simulations of an L-mode discharge on Alcator C-Mod |
| title_sort | mean flows and blob velocities in scrape off layer solt simulations of an l mode discharge on alcator c mod |
| url | http://hdl.handle.net/1721.1/113071 https://orcid.org/0000-0002-7841-9261 |
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