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Title: Edge localized mode suppression and plasma response using mixed toroidal harmonic resonant magnetic perturbations in DIII-D

Abstract

Edge localized mode (ELM) suppression has been achieved in the DIII-D tokamak using mixed toroidal n = 2 and 3 harmonic resonant magnetic perturbations (RMPs). Here n is the toroidal mode number. It is determined that mixed toroidal harmonic RMPs lower the threshold current for ELM suppression compared to the single n= 3 case. The decreased threshold suggests that mixed toroidal harmonic RMPs offer a better path to ELM control. The error field effect is studied by superimposing n = 2 error field correction upon the n = 2 phase scan, which shows that it is possible to suppress the ELM and correct the error field simultaneously. The plasma response calculated by magnetic sensors shows the n = 3 harmonic plays a key role in ELM suppression using mixed toroidal harmonic RMPs. A nonlinear jump in the n = 3 plasma response is observed during the bifurcation from mitigation to suppression of ELMs, similar to the n = 2 results reported in Nazikian et al (2015 Phys. Rev. Lett. 114 5). Magneto-hydrodynamic simulations using toroidal rotation find good agreement with the ELM mitigated phase when the input rotation profile is high and induces strong screening of the RMP. Simulations withmore » zero-crossing rotation find strong penetration of the RMP and reproduce the mode structure of ELM suppression on both the low and high field side. This indicates that edge components may penetrate during the transition from ELM mitigation to suppression.« less

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3];  [4]; ORCiD logo [1];  [2]; ORCiD logo [2];  [3];  [3];  [4];  [3]; ORCiD logo [3];  [2]; ORCiD logo [4]; ORCiD logo [3]; ORCiD logo [5];  [2]
  1. Chinese Academy of Sciences (CAS), Hefei (China). Inst. of Plasma Physics; Univ. of Science and Technology of China, Hefei (China)
  2. Chinese Academy of Sciences (CAS), Hefei (China). Inst. of Plasma Physics
  3. General Atomics, San Diego, CA (United States)
  4. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  5. Univ. of California, San Diego, CA (United States)
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States); Princeton Univ., NJ (United States); Univ. of California, San Diego, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24); National Key R&D Program of China; National Natural Science Foundation of China (NNSFC)
OSTI Identifier:
1557634
Grant/Contract Number:  
FC02-04ER54698; AC02-09CH11466; FG02-05ER54809
Resource Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 59; Journal Issue: 2; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ELM control; RMP; plasma response; error field correction

Citation Formats

Gu, S., Sun, Y., Paz-Soldan, C., Nazikian, R., Jia, M., Wang, H. H., Guo, W., Liu, Y. Q., Abrams, T., Cui, L., Evans, T., Garofalo, A., Gong, X., Logan, N. C., Munaretto, S., Orlov, D., and Shi, T. Edge localized mode suppression and plasma response using mixed toroidal harmonic resonant magnetic perturbations in DIII-D. United States: N. p., 2019. Web. doi:10.1088/1741-4326/aaf5a3.
Gu, S., Sun, Y., Paz-Soldan, C., Nazikian, R., Jia, M., Wang, H. H., Guo, W., Liu, Y. Q., Abrams, T., Cui, L., Evans, T., Garofalo, A., Gong, X., Logan, N. C., Munaretto, S., Orlov, D., & Shi, T. Edge localized mode suppression and plasma response using mixed toroidal harmonic resonant magnetic perturbations in DIII-D. United States. doi:10.1088/1741-4326/aaf5a3.
Gu, S., Sun, Y., Paz-Soldan, C., Nazikian, R., Jia, M., Wang, H. H., Guo, W., Liu, Y. Q., Abrams, T., Cui, L., Evans, T., Garofalo, A., Gong, X., Logan, N. C., Munaretto, S., Orlov, D., and Shi, T. Fri . "Edge localized mode suppression and plasma response using mixed toroidal harmonic resonant magnetic perturbations in DIII-D". United States. doi:10.1088/1741-4326/aaf5a3.
@article{osti_1557634,
title = {Edge localized mode suppression and plasma response using mixed toroidal harmonic resonant magnetic perturbations in DIII-D},
author = {Gu, S. and Sun, Y. and Paz-Soldan, C. and Nazikian, R. and Jia, M. and Wang, H. H. and Guo, W. and Liu, Y. Q. and Abrams, T. and Cui, L. and Evans, T. and Garofalo, A. and Gong, X. and Logan, N. C. and Munaretto, S. and Orlov, D. and Shi, T.},
abstractNote = {Edge localized mode (ELM) suppression has been achieved in the DIII-D tokamak using mixed toroidal n = 2 and 3 harmonic resonant magnetic perturbations (RMPs). Here n is the toroidal mode number. It is determined that mixed toroidal harmonic RMPs lower the threshold current for ELM suppression compared to the single n= 3 case. The decreased threshold suggests that mixed toroidal harmonic RMPs offer a better path to ELM control. The error field effect is studied by superimposing n = 2 error field correction upon the n = 2 phase scan, which shows that it is possible to suppress the ELM and correct the error field simultaneously. The plasma response calculated by magnetic sensors shows the n = 3 harmonic plays a key role in ELM suppression using mixed toroidal harmonic RMPs. A nonlinear jump in the n = 3 plasma response is observed during the bifurcation from mitigation to suppression of ELMs, similar to the n = 2 results reported in Nazikian et al (2015 Phys. Rev. Lett. 114 5). Magneto-hydrodynamic simulations using toroidal rotation find good agreement with the ELM mitigated phase when the input rotation profile is high and induces strong screening of the RMP. Simulations with zero-crossing rotation find strong penetration of the RMP and reproduce the mode structure of ELM suppression on both the low and high field side. This indicates that edge components may penetrate during the transition from ELM mitigation to suppression.},
doi = {10.1088/1741-4326/aaf5a3},
journal = {Nuclear Fusion},
number = 2,
volume = 59,
place = {United States},
year = {2019},
month = {1}
}

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