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Title: Injected mass deposition thresholds for lithium granule instigated triggering of edge localized modes on EAST

Abstract

The ability of an injected lithium granule to promptly trigger an edge localized mode (ELM) has been established in multiple experiments. By horizontally injecting granules ranging in diameter from 200 microns to 1mm in diameter into the low field side of EAST H-mode discharges we have determined that granules with diameter > 600 microns are successful in triggering ELMs more than 95% of the time. Granules were radially injected from the outer midplane with velocities ~ 80 m/s into EAST upper-single null discharges with an ITER like tungsten monoblock divertor. ELM triggering was a prompt response to granule injection, and for granules of a sufficient size there was no evidence of a "trigger lag" phenomenon as observed in full metal machines. We also demonstrated that the triggering efficiency decreased with granule size during dynamic size scans. These granules were individually tracked throughout their injection cycle in order to determine their efficacy at triggering an ELM. Furthermore, by simulating the granule injection with an experimentally benchmarked neutral gas shielding (NGS) model, the ablatant mass deposition required to promptly trigger an ELM is calculated and the fractional mass deposition is determined. Simulated 900 micron granules capable of triggering an ELM show amore » peaked mass deposition of 3.9 x 1017 atoms per mm of penetration at a depth of approximately 5 cm past the separatrix.« less

Authors:
 [1];  [2];  [1];  [2];  [1];  [2];  [2];  [1];  [3];  [4];  [5];  [2];  [6];  [2];  [2];  [2]
  1. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
  2. Chinese Academy of Sciences (CAS), Beijing (China). Inst. of Plasma Physics
  3. General Atomics, San Diego, CA (United States)
  4. Johns Hopkins Univ., Baltimore, MD (United States)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  6. Hunan Univ., Changsha (China). Dept. of Applied Physics
Publication Date:
Research Org.:
Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1414904
Grant/Contract Number:  
No.11321092; No.11405210; No.11605246; No.11625524; AC02-09CH11466; FC02-04ER54698; FG02-09ER55
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 58; Journal Issue: 3; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY

Citation Formats

Lunsford, R., Sun, Zhen, Maingi, Rajesh, Hu, Jiansheng, Mansfield, D. K., Xu, Wei, Zuo, Guizhong, Diallo, Ahmed, Osborne, Tom H., Tritz, Kevin, Canik, John M., Huang, Ming, Meng, Xiancai, Gong, Xianzu, Wan, Baonian, and Li, Jiangang. Injected mass deposition thresholds for lithium granule instigated triggering of edge localized modes on EAST. United States: N. p., 2017. Web. doi:10.1088/1741-4326/aaa2ac.
Lunsford, R., Sun, Zhen, Maingi, Rajesh, Hu, Jiansheng, Mansfield, D. K., Xu, Wei, Zuo, Guizhong, Diallo, Ahmed, Osborne, Tom H., Tritz, Kevin, Canik, John M., Huang, Ming, Meng, Xiancai, Gong, Xianzu, Wan, Baonian, & Li, Jiangang. Injected mass deposition thresholds for lithium granule instigated triggering of edge localized modes on EAST. United States. https://doi.org/10.1088/1741-4326/aaa2ac
Lunsford, R., Sun, Zhen, Maingi, Rajesh, Hu, Jiansheng, Mansfield, D. K., Xu, Wei, Zuo, Guizhong, Diallo, Ahmed, Osborne, Tom H., Tritz, Kevin, Canik, John M., Huang, Ming, Meng, Xiancai, Gong, Xianzu, Wan, Baonian, and Li, Jiangang. 2017. "Injected mass deposition thresholds for lithium granule instigated triggering of edge localized modes on EAST". United States. https://doi.org/10.1088/1741-4326/aaa2ac. https://www.osti.gov/servlets/purl/1414904.
@article{osti_1414904,
title = {Injected mass deposition thresholds for lithium granule instigated triggering of edge localized modes on EAST},
author = {Lunsford, R. and Sun, Zhen and Maingi, Rajesh and Hu, Jiansheng and Mansfield, D. K. and Xu, Wei and Zuo, Guizhong and Diallo, Ahmed and Osborne, Tom H. and Tritz, Kevin and Canik, John M. and Huang, Ming and Meng, Xiancai and Gong, Xianzu and Wan, Baonian and Li, Jiangang},
abstractNote = {The ability of an injected lithium granule to promptly trigger an edge localized mode (ELM) has been established in multiple experiments. By horizontally injecting granules ranging in diameter from 200 microns to 1mm in diameter into the low field side of EAST H-mode discharges we have determined that granules with diameter > 600 microns are successful in triggering ELMs more than 95% of the time. Granules were radially injected from the outer midplane with velocities ~ 80 m/s into EAST upper-single null discharges with an ITER like tungsten monoblock divertor. ELM triggering was a prompt response to granule injection, and for granules of a sufficient size there was no evidence of a "trigger lag" phenomenon as observed in full metal machines. We also demonstrated that the triggering efficiency decreased with granule size during dynamic size scans. These granules were individually tracked throughout their injection cycle in order to determine their efficacy at triggering an ELM. Furthermore, by simulating the granule injection with an experimentally benchmarked neutral gas shielding (NGS) model, the ablatant mass deposition required to promptly trigger an ELM is calculated and the fractional mass deposition is determined. Simulated 900 micron granules capable of triggering an ELM show a peaked mass deposition of 3.9 x 1017 atoms per mm of penetration at a depth of approximately 5 cm past the separatrix.},
doi = {10.1088/1741-4326/aaa2ac},
url = {https://www.osti.gov/biblio/1414904}, journal = {Nuclear Fusion},
issn = {0029-5515},
number = 3,
volume = 58,
place = {United States},
year = {Tue Dec 19 00:00:00 EST 2017},
month = {Tue Dec 19 00:00:00 EST 2017}
}

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Figures / Tables:

Table 1 Table 1: Injection parameters for high power granule discharges. aDischarge #70605 was undertaken immediately after switching granule sizes without clearing the crystal surface. As such the average granule size at the beginning of the discharge is larger than the sizes at the end. bFor the smallest granule sizes injected inmore » discharge #70607 the impeller was driving in multiple granules per pass, thus the actual frequency is capped by the 300 Hz impeller frequency. The uncertainty indicated in row 2 of column 3 is indicative of the uncertainty in all velocity estimates.« less

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Works referenced in this record:

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Non-linear MHD simulations of edge localized modes (ELMs)
journal, November 2009


Works referencing / citing this record:

Modeling of Ablatant Deposition from Electromagnetically Driven Radiative Pellets for Disruption Mitigation Studies
journal, July 2019


Fusion applications for lithium: wall conditioning in magnetic confinement devices
journal, October 2019