| Autor: |
Holcomb, CT, Heidbrink, WW, Ferron, JR, Van Zeeland, MA, Garofalo, AM, Solomon, WM, Gong, X, Mueller, D, Grierson, B, Bass, EM, Collins, C, Park, JM, Kim, K, Luce, TC, Turco, F, Pace, DC, Ren, Q, Podesta, M |
| Jazyk: |
angličtina |
| Rok vydání: |
2015 |
| Zdroj: |
Holcomb, CT; Heidbrink, WW; Ferron, JR; Van Zeeland, MA; Garofalo, AM; Solomon, WM; et al.(2015). Fast-ion transport in q min > 2, high-β steady-state scenarios on DIII-D. Physics of Plasmas, 22(5). doi: 10.1063/1.4921152. UC Irvine: Retrieved from: http://www.escholarship.org/uc/item/5bs4t3qn |
| DOI: |
10.1063/1.4921152. |
| Popis: |
© 2015 AIP Publishing LLC. Results from experiments on DIII-D [J. L. Luxon, Fusion Sci. Technol. 48, 828 (2005)] aimed at developing high β steady-state operating scenarios with high- q min confirm that fast-ion transport is a critical issue for advanced tokamak development using neutral beam injection current drive. In DIII-D, greater than 11 MW of neutral beam heating power is applied with the intent of maximizing β N and the noninductive current drive. However, in scenarios with q min > 2 that target the typical range of q 95 = 5-7 used in next-step steady-state reactor models, Alfvén eigenmodes cause greater fast-ion transport than classical models predict. This enhanced transport reduces the absorbed neutral beam heating power and current drive and limits the achievable βN. In contrast, similar plasmas except with q min just above 1 have approximately classical fast-ion transport. Experiments that take q min > 3 plasmas to higher β P with q 95 = 11-12 for testing long pulse operation exhibit regimes of better than expected thermal confinement. Compared to the standard high- q min scenario, the high β P cases have shorter slowing-down time and lower ∇ β fast, and this reduces the drive for Alfvénic modes, yielding nearly classical fast-ion transport, high values of normalized confinement, β N, and noninductive current fraction. These results suggest DIII-D might obtain better performance in lower- q 95, high- q min plasmas using broader neutral beam heating profiles and increased direct electron heating power to lower the drive for Alfvén eigenmodes. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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