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Disruptive neoclassical tearing mode seeding in DIII-D with implications for ITER

Journal Article · · Nuclear Fusion
 [1];  [2];  [2];  [3];  [3];  [4];  [5];  [6]
  1. General Atomics, San Diego, CA (United States); General Atomics, Energy & Advanced Concepts, DIII-D
  2. General Atomics, San Diego, CA (United States)
  3. Univ. of Wisconsin, Madison, WI (United States)
  4. Tech-X Corporation, Boulder, CO (United States)
  5. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  6. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
+ Show Author Affiliations
New studies identify the critical parameters and physics governing disruptive neoclassical tearing mode (NTM) onset. An m/n = 2/1 mode in DIII-D that begins to grow robustly after a seeding event (edge localized mode ELM or sawtooth precursor and crash) causes the mode rotation to drop close to the plasma's Er = 0 rest frame; this condition opens the stabilizing ion-polarization current 'gate' and destabilizes an otherwise marginally stable NTM. Our new experimental and theoretical insights and novel toroidal theory-based modeling are benchmarked and scalable to ITER and other future experiments. Here, the nominal ITER rotation at q = 2 is found to be stabilizing ('gate closed') except for MHD-induced transients that could 'open the gate'. Extrapolating from the DIII-D ITER baseline scenario (IBS) discharges, MHD transients are much more likely to destabilize problematic robustly growing 2/1 NTMs in ITER; this makes predictions of seeding and control of both ELMs and sawteeth imperative for more than just minimizing divertor pulsed-heat loading.
Research Organization:
General Atomics, San Diego, CA (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
Grant/Contract Number:
AC05-00OR22725; FC02-04ER54698
OSTI ID:
1863244
Alternate ID(s):
OSTI ID: 1869072
Journal Information:
Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 5 Vol. 62; ISSN 0029-5515
Publisher:
IOP ScienceCopyright Statement
Country of Publication:
United States
Language:
English

References (27)

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Effect of resonant magnetic perturbations on local plasma current density gradients and neoclassical tearing modes journal February 2021

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Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
stability
tearing
tokamak