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Title: Impact of ELM filaments on divertor heat flux dynamics in NSTX

Journal Article · · Journal of Nuclear Materials
 [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 Science, Hefei (China)
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
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In this study, the ELM induced change in wetted area (Awet) and peak heat flux (qpeak) of divertor heat flux is investigated as a function of the number of striations, which represent ELM filaments, observed in the heat flux profile in NSTX. More striations are found to lead to larger Awet and lower qpeak. The typical number of striations observed in NSTX is 0–9, while 10–15 striations are normally observed in other machines such as JET, and the ELM contracts heat flux profile when the number of striations is less than 3–4 but broadens it with more of them. The smaller number of striations in NSTX is attributed to the fact that NSTX ELMs are against kink/peeling boundary with lower toroidal mode number (n = 1–5), while typical peeling–ballooning ELMs have higher mode number of n = 10–20. For ELMs with smaller number of striations, relative Awet change is rather constant and qpeak change rapidly increases with increasing ELM size, while Awet change slightly increases leading to a weaker increase of qpeak change for ELMs with larger number of striations, both of which are unfavourable trend for the material integrity of divertor tiles.

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
Grant/Contract Number:
AC05-00OR22725; AC02-09CH11466; ORNL
OSTI ID:
1265985
Alternate ID(s):
OSTI ID: 1252280
Journal Information:
Journal of Nuclear Materials, Vol. 463; ISSN 0022-3115
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 2 works
Citation information provided by
Web of Science

References (10)

Progress on the application of ELM control schemes to ITER scenarios from the non-active phase to DT operation journal February 2014
Type-I ELM power deposition profile width and temporal shape in JET journal August 2011
Evolution of Filament Structures during Edge-Localized Modes in the MAST Tokamak journal May 2006
Type-I ELM filamentary substructure on the JET divertor target journal August 2011
Edge-Localized-Mode Suppression through Density-Profile Modification with Lithium-Wall Coatings in the National Spherical Torus Experiment journal August 2009
The relationships between edge localized modes suppression, pedestal profiles and lithium wall coatings in NSTX journal September 2011
Nonaxisymmetric Energy Deposition Pattern on ASDEX Upgrade Divertor Target Plates during Type-I Edge-Localized Modes journal November 2003
2D divertor heat flux distribution using a 3D heat conduction solver in National Spherical Torus Experiment journal February 2013
Full toroidal imaging of non-axisymmetric plasma material interaction in the National Spherical Torus Experiment divertor journal October 2012
A first-principles predictive model of the pedestal height and width: development, testing and ITER optimization with the EPED model journal August 2011

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