HIGH FUSION PERFORMANCE IN SUPER H-MODE EXPERIMENTS ON ALCATOR C-MOD AND DIII-D
- General Atomics, San Diego, CA (United States)
- MIT Plasma Science and Fusion Center, Cambridge, MA (United States)
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- College of William and Mary, Williamsburg, VA (United States)
- University of York (United Kingdom); Culham Center for Fusion Energy, Culham Science Centre, Abingdon, Oxon (United Kingdom)
- Univ. of California, Irvine, CA (United States)
The “Super H-Mode” regime is predicted to enable pedestal height and fusion performance substantially higher than standard H-Mode operation. This regime exists due to a bifurcation of the pedestal pressure, as a function of density, that is predicted by the EPED model to occur in strongly shaped plasmas above a critical pedestal density. Experiments on Alcator C-Mod and DIII-D have achieved access to the Super H-Mode (and Near Super H) regime, and obtained very high pedestal pressure, including the highest achieved on a tokamak (pped ~80 kPa) in C-Mod experiments operating near the ITER magnetic field. DIII-D Super H experiments have demonstrated strong performance, including the highest stored energy in the present configuration of DIII-D (W ~ 2.2-3.2MJ), while utilizing only about half of the available heating power (Pheat ~ 7-12 MW). These DIII-D experiments have obtained the highest value of peak fusion gain, Q DT, equiv ~ 0.5, achieved on a medium scale (R < 2m) tokamak. Sustained high performance operation (βN ~ 2.9, H98 ~ 1.6) has been achieved utilizing n = 3 magnetic perturbations for density and impurity control. Pedestal and global confinement have been maintained in the presence of deuterium and nitrogen gas puffing, which enables a more radiative divertor condition. Here, a pair of simple performance metrics is developed to assess and compare regimes. Super H-Mode access is predicted for ITER and expected, based on both theoretical prediction and observed normalized performance, to allow ITER to achieve its goals (Q = 10) at I p < 15MA, and to potentially enable more compact, cost effective pilot plant and reactor designs.
- Research Organization:
- General Atomics, San Diego, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- Grant/Contract Number:
- FG02-95ER54309; FC02-04ER54698; FC02-99ER54512; FC02-06ER54873; SC0014264; SC0017992
- OSTI ID:
- 1489822
- Alternate ID(s):
- OSTI ID: 1572159
- Journal Information:
- Nuclear Fusion, Vol. 59, Issue 8; ISSN 0029-5515
- Publisher:
- IOP ScienceCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
27th IAEA Fusion Energy Conference: summary of sessions EX/C, EX/S and PPC
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journal | January 2020 |
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