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Title: Broadening of divertor heat flux profile with increasing number of ELM filaments in NSTX

Edge localized modes (ELMs) represent a challenge to future fusion devices, owing to cyclical high peak heat fluxes on divertor plasma facing surfaces. One ameliorating factor has been that the heat flux characteristic profile width has been observed to broaden with the size of the ELM, as compared with the inter-ELM heat flux profile. In contrast, the heat flux profile has been observed to narrow during ELMs under certain conditions in NSTX. Here we show that the ELM heat flux profile width increases with the number of filamentary striations observed, i.e., profile narrowing is observed with zero or very few striations. Because NSTX often lies on the long wavelength current-driven mode side of ideal MHD instabilities, few filamentary structures can be expected under many conditions. Lastly, ITER is also projected to lie on the current driven low-n stability boundary, and therefore detailed projections of the unstable modes expected in ITER and the heat flux driven in ensuing filamentary structures is needed.
Authors:
 [1] ;  [2] ;  [1] ;  [3] ;  [1] ;  [4]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  3. Chinese Academy of Sciences (CAS), Hefei (China). Inst. of Plasma Physics
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
OSTI Identifier:
1305850
Report Number(s):
LLNL-JRNL--700288
Journal ID: ISSN 0029-5515
Grant/Contract Number:
AC52-07NA27344; AC02-09CH11466; AC05- 00OR22725; 2011GB107001
Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 54; Journal Issue: 12; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Research Org:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE; National Magnetic Confinement Fusion Science Program of China
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY ELM filament; divertor heat flux; NSTX