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Title: Advances in the steady-state hybrid regime in DIII-D – a fully non-inductive, ELM-suppressed scenario for ITER

Here, the hybrid regime with beta, collisionality, safety factor and plasma shape relevant to the ITER steady-state mission has been successfully integrated with ELM suppression by applying an odd parity n=3 resonant magnetic perturbation (RMP). Fully non-inductive hybrids in the DIII-D tokamak with high beta (β ≤ 2.8%) and high confinement (98y2 ≤ 1.4) in the ITER similar shape have achieved zero surface loop voltage for up to two current relaxation times using efficient central current drive from ECCD and NBCD. The n=3 RMP causes surprisingly little increase in thermal transport during ELM suppression. Poloidal magnetic flux pumping in hybrid plasmas maintains q above 1 without loss of current drive efficiency, except that experiments show that extremely peaked ECCD profiles can create sawteeth. During ECCD, Alfvén eigenmode (AE) activity is replaced by a more benign fishbone-like mode, reducing anomalous beam ion diffusion by a factor of 2. While the electron and ion thermal diffusivities substantially increase with higher ECCD power, the loss of confinement can be offset by the decreased fast ion transport resulting from AE suppression. Extrapolations from DIII-D along a dimensionless parameter scaling path as well as those using self-consistent theory-based modeling show that these ELM-suppressed, fully non-inductivemore » hybrids can achieve the Q = 5 ITER steady-state mission.« less
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  1. General Atomics, San Diego, CA (United States)
  2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. Columbia Univ., New York, NY (United States)
  5. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  6. Univ. of Wisconsin, Madison, WI (United States)
  7. Univ. of California San Diego, La Jolla, CA (United States)
  8. Oak Ridge Associated Univ., Oak Ridge, TN (United States)
  9. Univ. of California, Irvine, CA (United States)
Publication Date:
Grant/Contract Number:
AC05-06OR23100; AC02-09CH11466; FC02-05ER54809; FG02-04ER54761; FG02-08ER54999; AC52-07NA27344; FC02-04ER54698; SC-G903402
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 57; Journal Issue: 11; Journal ID: ISSN 0029-5515
IOP Science
Research Org:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); General Atomics, San Diego, CA (United States)
Sponsoring Org:
Country of Publication:
United States
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1374556