Exploring Experimental Isotope Scaling and Density Limit in Tokamak Transport
As it turns out, both isotope scaling and density limits are phenomena closely linked to fluid closure. The necessity to include ion viscosity arises for both phenomena. Thus, we have added ion viscosity to our model. The experimental isotope scaling has been successfully recovered in our fluid mode...
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MDPI AG
2024-09-01
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| author | Jan Weiland Tariq Rafiq Eugenio Schuster |
| author_facet | Jan Weiland Tariq Rafiq Eugenio Schuster |
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| description | As it turns out, both isotope scaling and density limits are phenomena closely linked to fluid closure. The necessity to include ion viscosity arises for both phenomena. Thus, we have added ion viscosity to our model. The experimental isotope scaling has been successfully recovered in our fluid model through parameter scans. Although ion viscosity typically exerts a small effect, the density limit is manifested by increasing the density by approximately tenfold from the typical experimental density. In our case, this increase originates from the density in the Cyclone base case. Notably, these phenomena would not manifest with a gyro-Landau fluid closure. The isotope scaling is nullified by the addition of a gyro-Landau term, while the density limit results from permitting ion viscosity to become comparable to the gyro-Landau term. The mechanism of zonal flows, demonstrated analytically for the Dimits upshift, yields insights into the isotope scaling observed in experiments. In our approach, ion viscosity is introduced in place of the Landau fluid resonances found in some fluid models. This implies that the mechanism of isotope scaling operates at the level of fluid closure in connection with the generation of zonal flows. The strength of zonal flows in our model has been verified, particularly in connection with the successful simulation of the nonlinear Dimits shift. Consequently, a role is played by our approach in the temperature perturbation part of the Reynolds stress. |
| format | Article |
| id | doaj-art-78f92acae506401fb8c4f5b5797eff4c |
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| publishDate | 2024-09-01 |
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| spelling | doaj-art-78f92acae506401fb8c4f5b5797eff4c2025-08-20T01:55:48ZengMDPI AGPlasma2571-61822024-09-017378079210.3390/plasma7030041Exploring Experimental Isotope Scaling and Density Limit in Tokamak TransportJan Weiland0Tariq Rafiq1Eugenio Schuster2Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18017, USADepartment of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18017, USADepartment of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18017, USAAs it turns out, both isotope scaling and density limits are phenomena closely linked to fluid closure. The necessity to include ion viscosity arises for both phenomena. Thus, we have added ion viscosity to our model. The experimental isotope scaling has been successfully recovered in our fluid model through parameter scans. Although ion viscosity typically exerts a small effect, the density limit is manifested by increasing the density by approximately tenfold from the typical experimental density. In our case, this increase originates from the density in the Cyclone base case. Notably, these phenomena would not manifest with a gyro-Landau fluid closure. The isotope scaling is nullified by the addition of a gyro-Landau term, while the density limit results from permitting ion viscosity to become comparable to the gyro-Landau term. The mechanism of zonal flows, demonstrated analytically for the Dimits upshift, yields insights into the isotope scaling observed in experiments. In our approach, ion viscosity is introduced in place of the Landau fluid resonances found in some fluid models. This implies that the mechanism of isotope scaling operates at the level of fluid closure in connection with the generation of zonal flows. The strength of zonal flows in our model has been verified, particularly in connection with the successful simulation of the nonlinear Dimits shift. Consequently, a role is played by our approach in the temperature perturbation part of the Reynolds stress.https://www.mdpi.com/2571-6182/7/3/41isotope scalingdensity limitturbulence and transport modelingmagnetic confinementresonance broadeningtokamaks |
| spellingShingle | Jan Weiland Tariq Rafiq Eugenio Schuster Exploring Experimental Isotope Scaling and Density Limit in Tokamak Transport Plasma isotope scaling density limit turbulence and transport modeling magnetic confinement resonance broadening tokamaks |
| title | Exploring Experimental Isotope Scaling and Density Limit in Tokamak Transport |
| title_full | Exploring Experimental Isotope Scaling and Density Limit in Tokamak Transport |
| title_fullStr | Exploring Experimental Isotope Scaling and Density Limit in Tokamak Transport |
| title_full_unstemmed | Exploring Experimental Isotope Scaling and Density Limit in Tokamak Transport |
| title_short | Exploring Experimental Isotope Scaling and Density Limit in Tokamak Transport |
| title_sort | exploring experimental isotope scaling and density limit in tokamak transport |
| topic | isotope scaling density limit turbulence and transport modeling magnetic confinement resonance broadening tokamaks |
| url | https://www.mdpi.com/2571-6182/7/3/41 |
| work_keys_str_mv | AT janweiland exploringexperimentalisotopescalinganddensitylimitintokamaktransport AT tariqrafiq exploringexperimentalisotopescalinganddensitylimitintokamaktransport AT eugenioschuster exploringexperimentalisotopescalinganddensitylimitintokamaktransport |