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Title: ELM mitigation with pellet ELM triggering and implications for PFCs and plasma performance in ITER

Journal Article · · Journal of Nuclear Materials
 [1];  [2];  [3];  [1];  [1];  [4];  [3];  [5];  [1];  [3];  [4];  [5];  [6];  [5];  [1];  [7];  [4]
  1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  2. Max Planck Inst. fur Plasmaphysik, Garching (Germany)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  4. General Atomics, San Diego, CA (United States)
  5. ITER Organization, St. Paul Lez Durance (France)
  6. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  7. Univ. of California, San Diego, CA (United States)
+ Show Author Affiliations

The triggering of rapid small edge localized modes (ELMs) by high frequency pellet injection has been proposed as a method to prevent large naturally occurring ELMs that can erode the ITER plasma facing components. Deuterium pellet injection has been used to successfully demonstrate the on-demand triggering of edge localized modes (ELMs) at much higher rates and with much smaller intensity than natural ELMs. The proposed hypothesis for the triggering mechanism of ELMs by pellets is the local pressure perturbation resulting from reheating of the pellet cloud that can exceed the local high-n ballooning mode threshold where the pellet is injected. Nonlinear MHD simulations of the pellet ELM triggering show destabilization of high-n ballooning modes by such a local pressure perturbation. A review of the recent pellet ELM triggering results from ASDEX Upgrade (AUG), DIII-D, and JET reveals that a number of uncertainties about this ELM mitigation technique still remain. These include the heat flux impact pattern on the divertor and wall from pellet triggered and natural ELMs, the necessary pellet size and injection location to reliably trigger ELMs, and the level of fueling to be expected from ELM triggering pellets and synergy with larger fueling pellets. The implications of these issues for pellet ELM mitigation in ITER and its impact on the PFCs are presented along with the design features of the pellet injection system for ITER.

Research Organization:
General Atomics, San Diego, CA (United States)
Sponsoring Organization:
USDOE
Grant/Contract Number:
FC02-04ER54698; AC05-00OR22725; FG02-07ER54917; AC52-07NA27344
OSTI ID:
1375959
Alternate ID(s):
OSTI ID: 1252293
Journal Information:
Journal of Nuclear Materials, Vol. 463, Issue C; ISSN 0022-3115
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 12 works
Citation information provided by
Web of Science

References (18)

Edge localized modes (ELMs) journal February 1996
Progress on the application of ELM control schemes to ITER scenarios from the non-active phase to DT operation journal February 2014
Reduction of Edge-Localized Mode Intensity Using High-Repetition-Rate Pellet Injection in Tokamak H -Mode Plasmas journal June 2013
ELM pace making and mitigation by pellet injection in ASDEX Upgrade journal April 2004
ELM pacing investigations at JET with the new pellet launcher journal March 2011
Modeling of stochastic magnetic flux loss from the edge of a poloidally diverted tokamak journal December 2002
Blob Transport in the Plasma Edge: a Review journal January 2009
Evolution and stratification of a plasma cloud surrounding a pellet journal April 1995
Edge-localized mode dynamics and transport in the scrape-off layer of the DIII-D tokamak journal July 2005
Investigation of pellet-triggered MHD events in ASDEX Upgrade and JET journal August 2008
ELM pacing and high-density operation using pellet injection in the ASDEX Upgrade all-metal-wall tokamak journal June 2014
ELM control strategies and tools: status and potential for ITER journal March 2013
Type-I ELM power deposition profile width and temporal shape in JET journal August 2011
Multi-parameter scaling of divertor power load profiles in D, H and He plasmas on JET and implications for ITER journal July 2011
Reduction of edge localized mode intensity on DIII-D by on-demand triggering with high frequency pellet injection and implications for ITER journal August 2013
Non-linear MHD modelling of ELM triggering by pellet injection in DIII-D and implications for ITER journal April 2014
Overview of recent developments in pellet injection for ITER journal August 2012
Comparison of deuterium pellet injection from different locations on the DIII-D tokamak journal October 2007

Cited By (3)

Numerical simulation of the effect of pellet injection on ELMs journal June 2019
Non-linear magnetohydrodynamic simulations of plasma instabilities from pellet injection in Large Helical Device plasma journal August 2019
Pellet-Injector Technology—Brief History and Key Developments in the Last 25 Years journal December 2017

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Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
Plasma properties
Gases
Gas injection & Fueling
Pellet
DIII-D
ELM