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Title: Pellet Dropper Devices for ELM Control on DIII-D

Abstract

On several experimental tokamaks, pellet injection has been found to trigger edge localized modes (ELMs) in H-mode plasmas. This can provide a technique for ELM amelioration by reducing the ELM size with small high-frequency pellets. The key for success appears to be small pellets that penetrate just beyond the separatix, enough to trigger an ELM, but not enough to strongly fuel the plasma. To provide a source of small pellets, a pellet dropper device has been developed at the Oak Ridge National Laboratory and installed on the DIII-D tokamak. The pellet dropper consists of a batch extruder with an exit nozzle to provide a filament of solid deuterium (nominal 1-mm diameter), from which pellets are punched/dropped at rates of up to ≈50 Hz and at speeds of <10 m/s. The pellets are propelled directly downward and through a vertical injection port on DIII-D. In this paper, the design and the initial test results are presented, and the installation on DIII-D is described.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1];  [2];  [1];  [1]
  1. ORNL
  2. General Atomics, San Diego
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
929344
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Conference
Resource Relation:
Conference: 22nd IEEE/NPSS Symposium on Fusion Engineering, Albuquerque, NM, USA, 20070617, 20070621
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; DESIGN; DEUTERIUM; DOUBLET-3 DEVICE; EDGE LOCALIZED MODES; NOZZLES; ORNL; PELLET INJECTION; PELLETS; PLASMA; ELM Control; Pellet Injection; Plasma; Tokamak

Citation Formats

Combs, Stephen Kirk, Baylor, Larry R, Foust, Charles R, McGill, James M, Caughman, John B, Fehling, Dan T, Hansink, M. J., Jernigan, Thomas C, and Rasmussen, David A. Pellet Dropper Devices for ELM Control on DIII-D. United States: N. p., 2007. Web.
Combs, Stephen Kirk, Baylor, Larry R, Foust, Charles R, McGill, James M, Caughman, John B, Fehling, Dan T, Hansink, M. J., Jernigan, Thomas C, & Rasmussen, David A. Pellet Dropper Devices for ELM Control on DIII-D. United States.
Combs, Stephen Kirk, Baylor, Larry R, Foust, Charles R, McGill, James M, Caughman, John B, Fehling, Dan T, Hansink, M. J., Jernigan, Thomas C, and Rasmussen, David A. Mon . "Pellet Dropper Devices for ELM Control on DIII-D". United States.
@article{osti_929344,
title = {Pellet Dropper Devices for ELM Control on DIII-D},
author = {Combs, Stephen Kirk and Baylor, Larry R and Foust, Charles R and McGill, James M and Caughman, John B and Fehling, Dan T and Hansink, M. J. and Jernigan, Thomas C and Rasmussen, David A},
abstractNote = {On several experimental tokamaks, pellet injection has been found to trigger edge localized modes (ELMs) in H-mode plasmas. This can provide a technique for ELM amelioration by reducing the ELM size with small high-frequency pellets. The key for success appears to be small pellets that penetrate just beyond the separatix, enough to trigger an ELM, but not enough to strongly fuel the plasma. To provide a source of small pellets, a pellet dropper device has been developed at the Oak Ridge National Laboratory and installed on the DIII-D tokamak. The pellet dropper consists of a batch extruder with an exit nozzle to provide a filament of solid deuterium (nominal 1-mm diameter), from which pellets are punched/dropped at rates of up to ≈50 Hz and at speeds of <10 m/s. The pellets are propelled directly downward and through a vertical injection port on DIII-D. In this paper, the design and the initial test results are presented, and the installation on DIII-D is described.},
doi = {},
url = {https://www.osti.gov/biblio/929344}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2007},
month = {1}
}

Conference:
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