Multispecies density peaking in gyrokinetic turbulence simulations of low collisionality Alcator C-Mod plasmas
Peaked density profiles in low-collisionality AUG and JET H-mode plasmas are probably caused by a turbulently driven particle pinch, and Alcator C-Mod experiments confirmed that collisionality is a critical parameter. Density peaking in reactors could produce a number of important effects, some bene...
| Main Authors: | , , , , , , , , , , , , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
American Institute of Physics (AIP)
2017
|
| Online Access: | http://hdl.handle.net/1721.1/111203 https://orcid.org/0000-0002-4438-729X https://orcid.org/0000-0002-0026-6939 https://orcid.org/0000-0001-8319-5971 |
| _version_ | 1811096573185097728 |
|---|---|
| author | Mikkelsen, D. R. Bitter, M. Delgado-Aparicio, L. Hill, K. W. Candy, J. Waltz, R. E. Howard, Nathaniel Thomas Hughes Jr, Jerry Reinke, Matthew Logan Ma, Y. Greenwald, Martin J. Rice, John E. Podpaly, Yuri |
| author2 | Massachusetts Institute of Technology. Department of Nuclear Science and Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Mikkelsen, D. R. Bitter, M. Delgado-Aparicio, L. Hill, K. W. Candy, J. Waltz, R. E. Howard, Nathaniel Thomas Hughes Jr, Jerry Reinke, Matthew Logan Ma, Y. Greenwald, Martin J. Rice, John E. Podpaly, Yuri |
| author_sort | Mikkelsen, D. R. |
| collection | MIT |
| description | Peaked density profiles in low-collisionality AUG and JET H-mode plasmas are probably caused by a turbulently driven particle pinch, and Alcator C-Mod experiments confirmed that collisionality is a critical parameter. Density peaking in reactors could produce a number of important effects, some beneficial, such as enhanced fusion power and transport of fuel ions from the edge to the core, while others are undesirable, such as lower beta limits, reduced radiation from the plasma edge, and consequently higher divertor heat loads. Fundamental understanding of the pinch will enable planning to optimize these impacts. We show that density peaking is predicted by nonlinear gyrokinetic turbulence simulations based on measured profile data from low collisionality H-mode plasma in Alcator C-Mod. Multiple ion species are included to determine whether hydrogenic density peaking has an isotope dependence or is influenced by typical levels of low-Z impurities, and whether impurity density peaking depends on the species. We find that the deuterium density profile is slightly more peaked than that of hydrogen, and that experimentally relevant levels of boron have no appreciable effect on hydrogenic density peaking. The ratio of density at r/a = 0.44 to that at r/a = 0.74 is 1.2 for the majority D and minority H ions (and for electrons), and increases with impurity Z: 1.1 for helium, 1.15 for boron, 1.3 for neon, 1.4 for argon, and 1.5 for molybdenum. The ion temperature profile is varied to match better the predicted heat flux with the experimental transport analysis, but the resulting factor of two change in heat transport has only a weak effect on the predicted density peaking. |
| first_indexed | 2024-09-23T16:45:50Z |
| format | Article |
| id | mit-1721.1/111203 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T16:45:50Z |
| publishDate | 2017 |
| publisher | American Institute of Physics (AIP) |
| record_format | dspace |
| spelling | mit-1721.1/1112032023-02-26T02:23:24Z Multispecies density peaking in gyrokinetic turbulence simulations of low collisionality Alcator C-Mod plasmas Mikkelsen, D. R. Bitter, M. Delgado-Aparicio, L. Hill, K. W. Candy, J. Waltz, R. E. Howard, Nathaniel Thomas Hughes Jr, Jerry Reinke, Matthew Logan Ma, Y. Greenwald, Martin J. Rice, John E. Podpaly, Yuri Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Massachusetts Institute of Technology. Plasma Science and Fusion Center Greenwald, Martin J Howard, Nathaniel Thomas Hughes Jr, Jerry Rice, John E Reinke, Matthew Logan Podpaly, Yuri A Ma, Y. Peaked density profiles in low-collisionality AUG and JET H-mode plasmas are probably caused by a turbulently driven particle pinch, and Alcator C-Mod experiments confirmed that collisionality is a critical parameter. Density peaking in reactors could produce a number of important effects, some beneficial, such as enhanced fusion power and transport of fuel ions from the edge to the core, while others are undesirable, such as lower beta limits, reduced radiation from the plasma edge, and consequently higher divertor heat loads. Fundamental understanding of the pinch will enable planning to optimize these impacts. We show that density peaking is predicted by nonlinear gyrokinetic turbulence simulations based on measured profile data from low collisionality H-mode plasma in Alcator C-Mod. Multiple ion species are included to determine whether hydrogenic density peaking has an isotope dependence or is influenced by typical levels of low-Z impurities, and whether impurity density peaking depends on the species. We find that the deuterium density profile is slightly more peaked than that of hydrogen, and that experimentally relevant levels of boron have no appreciable effect on hydrogenic density peaking. The ratio of density at r/a = 0.44 to that at r/a = 0.74 is 1.2 for the majority D and minority H ions (and for electrons), and increases with impurity Z: 1.1 for helium, 1.15 for boron, 1.3 for neon, 1.4 for argon, and 1.5 for molybdenum. The ion temperature profile is varied to match better the predicted heat flux with the experimental transport analysis, but the resulting factor of two change in heat transport has only a weak effect on the predicted density peaking. United States. Department of Energy (Contract DE-AC02-09CH11466) United States. Department of Energy (Contract DE-FC02-99ER54512) United States. Department of Energy (Contract DE-FG02-95ER54309) 2017-09-13T20:12:57Z 2017-09-13T20:12:57Z 2015-06 2015-03 Article http://purl.org/eprint/type/JournalArticle 1070-664X 1089-7674 http://hdl.handle.net/1721.1/111203 Mikkelsen, D. R. et al. “Multispecies Density Peaking in Gyrokinetic Turbulence Simulations of Low Collisionality Alcator C-Mod Plasmas.” Physics of Plasmas 22, 6 (June 2015): 062301 © 2015 American Institute of Physics (AIP) https://orcid.org/0000-0002-4438-729X https://orcid.org/0000-0002-0026-6939 https://orcid.org/0000-0001-8319-5971 en_US http://dx.doi.org/10.1063/1.4922069 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 | Mikkelsen, D. R. Bitter, M. Delgado-Aparicio, L. Hill, K. W. Candy, J. Waltz, R. E. Howard, Nathaniel Thomas Hughes Jr, Jerry Reinke, Matthew Logan Ma, Y. Greenwald, Martin J. Rice, John E. Podpaly, Yuri Multispecies density peaking in gyrokinetic turbulence simulations of low collisionality Alcator C-Mod plasmas |
| title | Multispecies density peaking in gyrokinetic turbulence simulations of low collisionality Alcator C-Mod plasmas |
| title_full | Multispecies density peaking in gyrokinetic turbulence simulations of low collisionality Alcator C-Mod plasmas |
| title_fullStr | Multispecies density peaking in gyrokinetic turbulence simulations of low collisionality Alcator C-Mod plasmas |
| title_full_unstemmed | Multispecies density peaking in gyrokinetic turbulence simulations of low collisionality Alcator C-Mod plasmas |
| title_short | Multispecies density peaking in gyrokinetic turbulence simulations of low collisionality Alcator C-Mod plasmas |
| title_sort | multispecies density peaking in gyrokinetic turbulence simulations of low collisionality alcator c mod plasmas |
| url | http://hdl.handle.net/1721.1/111203 https://orcid.org/0000-0002-4438-729X https://orcid.org/0000-0002-0026-6939 https://orcid.org/0000-0001-8319-5971 |
| work_keys_str_mv | AT mikkelsendr multispeciesdensitypeakingingyrokineticturbulencesimulationsoflowcollisionalityalcatorcmodplasmas AT bitterm multispeciesdensitypeakingingyrokineticturbulencesimulationsoflowcollisionalityalcatorcmodplasmas AT delgadoapariciol multispeciesdensitypeakingingyrokineticturbulencesimulationsoflowcollisionalityalcatorcmodplasmas AT hillkw multispeciesdensitypeakingingyrokineticturbulencesimulationsoflowcollisionalityalcatorcmodplasmas AT candyj multispeciesdensitypeakingingyrokineticturbulencesimulationsoflowcollisionalityalcatorcmodplasmas AT waltzre multispeciesdensitypeakingingyrokineticturbulencesimulationsoflowcollisionalityalcatorcmodplasmas AT howardnathanielthomas multispeciesdensitypeakingingyrokineticturbulencesimulationsoflowcollisionalityalcatorcmodplasmas AT hughesjrjerry multispeciesdensitypeakingingyrokineticturbulencesimulationsoflowcollisionalityalcatorcmodplasmas AT reinkematthewlogan multispeciesdensitypeakingingyrokineticturbulencesimulationsoflowcollisionalityalcatorcmodplasmas AT may multispeciesdensitypeakingingyrokineticturbulencesimulationsoflowcollisionalityalcatorcmodplasmas AT greenwaldmartinj multispeciesdensitypeakingingyrokineticturbulencesimulationsoflowcollisionalityalcatorcmodplasmas AT ricejohne multispeciesdensitypeakingingyrokineticturbulencesimulationsoflowcollisionalityalcatorcmodplasmas AT podpalyyuri multispeciesdensitypeakingingyrokineticturbulencesimulationsoflowcollisionalityalcatorcmodplasmas |