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Transport simulation of ELM pacing by pellet injection in tokamak plasmas

Cited 2 time in Web of Science Cited 3 time in Scopus
Issue Date
2010-04-23
Publisher
International Atomic Energy Agency (IAEA)
Citation
Nucl. Fusion 50(5) 055002 (2010)
Keywords
edge localized mode (ELM)ELM pacingpellet injectiontransport simulationtokamak plasmas
Abstract
This paper deals mainly with the numerical simulation on edge localized mode (ELM) pacing by pellet injection that is useful for fuelling and control of plasma profiles to achieve enhanced tokamak operations. The fuelling and pellet-induced ELMs are simulated with a 1.5-dimensional core transport code, which includes a neutral gas shielding model and a grad-B drift model for pellet deposition in H-mode tokamak plasmas. Fuelling and ELM pacing experiments by pellet injections at JET are introduced as a current experimental approach. For the description of ELM triggering by pellet injection based on ideal ballooning mode criteria, three possible models are suggested and discussed on their ELM characteristics, respectively: (i) the density enhanced ELMs in the post-pellet phase, (ii) the modification of the surface averaged pressure profiles in a transport time scale and (iii) the local increase in the pressure (density and/or temperature) gradients perturbed by pellets. Among them, the pellet-induced density perturbation model is adopted, in practice, to carry out an ELM pacing simulation in preparation for future experiments in KSTAR. The numerical simulation shows that the artificially induced ELM by pellets releases the reduced energy bursts, compared with spontaneous ELMs. The energy loss per burst by the pellet-induced ELM turns out to be much smaller than that by the spontaneous ELM as the pellet injection frequency becomes higher in ELM pacing. Based on the simulation results showing good agreement with the general ELM characteristics observed in pellet pacing experiments, the ELM pacing by pellet injection is very promising for mitigating the ELM energy bursts to the divertor by controlling the injection frequency.
ISSN
0029-5515
Language
English
URI
https://hdl.handle.net/10371/69099
DOI
https://doi.org/10.1088/0029-5515/50/5/055002
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College of Engineering/Engineering Practice School (공과대학/대학원)Dept. of Energy Systems Engineering (에너지시스템공학부)Nuclear Engineering (원자핵공학전공)Journal Papers (저널논문_원자핵공학과)
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