Advances in the Understanding of ELM Suppression by Resonant Magnetic Perturbations (RMPs) in DIII-D and Implications for ITER
- PPPL
Experiments on DIII-D have expanding the operating window for RMP ELM suppression to higher q95 with dominant electron heating and fully non-inductive current drive relevant to advanced modes of ITER operation. Robust ELM suppression has also been obtained with a reduced coil set, mitigating the risk of coil failure in maintaining ELM suppression in ITER. These results significantly expand the operating space and reduce risk for obtaining RMP ELM suppression in ITER. Efforts have also been made to search for 3D cause of ELM suppression. No internal non-axisymmetric structure is detected at the top of the pedestal, indicating that the dominant effect of the RMP is to produce an n=0 transport modification of the profiles. Linear two fluid MHD simulations using M3D-C1 indicate resonant field penetration and significant magnetic stochasticity at the top of the pedestal, consistent with the absence of detectable 3D structure in that region. A profile database was developed to compare the scaling of the pedestal and global confinement with the applied 3D field strength in ELM suppressed and ELM mitigated plasmas. The EPED pedestal model accurately predicts the measured pedestal pressure at the threshold of ELM suppression, increasing confidence in theoretical projections to ITER pedestal conditions. Both the H-factor (H(sub)98y2) and thermal energy confinement time do not degrade substantially with applied RMP fields near the threshold of ELM suppression, enhancing confidence in the compatibility of ITER high performance operation with RMP ELM suppression.
- Research Organization:
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Sponsoring Organization:
- USDOE
- Contributing Organization:
- 1) Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451, USA 2) University of California San Diego, La Jolla, California 92093-0417, USA 3) General Atomics, San Diego, California 92186-5608, USA 4) Oak Ridge Institute for Science Education, Oak Ridge, Tennessee 37830, USA 5) University of Wisconsin, Madison, Wisconsin 53706, USA 6) University of California Los Angeles, Los Angeles, California 90095-7099, USA 7) Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
- DOE Contract Number:
- DE-AC02-09CH11466
- OSTI ID:
- 1182663
- Report Number(s):
- PPPL-5075
- Journal Information:
- 25th IAEA Fusion Energy Conference Proceedings on IAEA Physics website, Conference: 25th IAEA Fusion Energy Conference, St. Petersburg, Russia, 13-18 October 2014.
- Publisher:
- IAEA
- Country of Publication:
- United States
- Language:
- English
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