Advances in the physics understanding of ELM suppression using resonant magnetic perturbations in DIII-D
- General Atomics, San Diego, CA (United States)
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Univ. of California, San Diego, CA (United States)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Univ. of Wisconsin, Madison, WI (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Max-Planck-Institut fur Plasmaphysik, Garching (Germany). IPP-Garching
- Univ. of California, Los Angeles, CA (United States)
We report recent experiments on DIII-D have increased confidence in the ability to suppress edge-localized modes (ELMs) using edge-resonant magnetic perturbations (RMPs) in ITER, including an improved physics basis for the edge response to RMPs as well as expansion of RMP ELM suppression to more ITER-like conditions. Complete ELM suppression has been achieved utilizing n = 3 RMPs in the ITER baseline scenario. In addition, RMP ELM suppression has been expanded to include plasmas with helium concentrations near 25% and the use of n = 2 RMPs. Analysis of the kinetic profile response suggests that ELM suppression is correlated with the co-alignment of the ω⊥e = 0 location, an n = 3 rational surface, and the top of the pedestal. Modelling predicts that such a co-alignment could potentially lead to island (or island chain) formation just inside the top of the pedestal, inhibiting the growth of the pedestal and thereby maintaining the ELM-free state. Detailed analysis of data obtained during toroidal phase variations of the applied n = 3 RMPs have provided further evidence of an island-like structure at the top of the pedestal. In addition, nearly matched discharges with co-neutral-beam-injection (co-NBI) and counter-NBI have demonstrated the importance of the presence of the ω⊥e = 0 location for ELM suppression. In the counter-NBI cases, the toroidal rotation profile is such that there is no ω⊥e = 0 location and ELMs are not suppressed in conditions in which ELM suppression is generally observed with co-NBI.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); General Atomics, San Diego, CA (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE Advanced Research Projects Agency - Energy (ARPA-E); USDOE National Nuclear Security Administration (NNSA)
- Grant/Contract Number:
- AC05-00OR22725; AC02-09CH11466; AC52-07NA27344; FC02-04ER54698; FG02-07ER54917; FG02-08ER54984; FG02-89ER53296; FG02-08ER54999
- OSTI ID:
- 1265638
- Alternate ID(s):
- OSTI ID: 1260806; OSTI ID: 1351086; OSTI ID: 1871390
- Report Number(s):
- LLNL-JRNL-834461; GA-A27695
- Journal Information:
- Nuclear Fusion, Vol. 55, Issue 2; ISSN 0029-5515
- Publisher:
- IOP ScienceCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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