skip to main content

DOE PAGESDOE PAGES

This content will become publicly available on December 19, 2018

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

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 10 17 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:
Grant/Contract Number:
No.11321092; No.11405210; No.11605246; No.11625524; AC02-09CH11466; FC02-04ER54698; FG02-09ER55
Type:
Accepted Manuscript
Journal Name:
Nuclear Fusion
Additional Journal Information:
Journal Volume: 58; Journal Issue: 3; Journal ID: ISSN 0029-5515
Publisher:
IOP Science
Research Org:
Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
OSTI Identifier:
1414904