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Title: Improved core fueling with high field side pellet injection in the DIII-D tokamak

Abstract

The capability to inject deuterium pellets from the magnetic high field side (HFS) has been added to the DIII-D tokamak [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)]. It is observed that pellets injected from the HFS lead to deeper mass deposition than identical pellets injected from the outside midplane, in spite of a factor of 4 lower pellet speed. HFS injected pellets have been used to generate peaked density profile plasmas [peaking factor (n{sub e}(0)/<n{sub e}>) in excess of 3] that develop internal transport barriers when centrally heated with neutral beam injection. The transport barriers are formed in conditions where T{sub e}{approx}T{sub i} and q(0) is above unity. The peaked density profiles, characteristic of the internal transport barrier, persist for several energy confinement times. The pellets are also used to investigate transport barrier physics and modify plasma edge conditions. Transitions from L- to H-mode have been triggered by pellets, effectively lowering the H-mode threshold power by 2.4 MW. Pellets injected into H-mode plasmas are found to trigger edge localized modes (ELMs). ELMs triggered from the low field side (LFS) outside midplane injected pellets are of significantly longer duration than from HFS injected pellets. (c) 2000more » American Institute of Physics.« less

Authors:
 [1];  [1];  [1];  [1];  [1];  [2];  [2];  [2];  [2];  [3]
  1. Oak Ridge National Laboratory, Oak Ridge, Tennessee (United States)
  2. General Atomics, San Diego, California (United States)
  3. General Atomics, San Diego, California (United States) (and others)
Publication Date:
OSTI Identifier:
20216056
Resource Type:
Journal Article
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 7; Journal Issue: 5; Other Information: PBD: May 2000; Journal ID: ISSN 1070-664X
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; PELLET INJECTION; TOKAMAK DEVICES; THERMONUCLEAR REACTOR FUELING; OPERATION; THERMONUCLEAR IGNITION; PLASMA DENSITY; EXPERIMENTAL DATA

Citation Formats

Baylor, L. R., Jernigan, T. C., Combs, S. K., Houlberg, W. A., Murakami, M., Gohil, P., Burrell, K. H., Greenfield, C. M., Groebner, R. J., and Hsieh, C.-L. Improved core fueling with high field side pellet injection in the DIII-D tokamak. United States: N. p., 2000. Web. doi:10.1063/1.874011.
Baylor, L. R., Jernigan, T. C., Combs, S. K., Houlberg, W. A., Murakami, M., Gohil, P., Burrell, K. H., Greenfield, C. M., Groebner, R. J., & Hsieh, C.-L. Improved core fueling with high field side pellet injection in the DIII-D tokamak. United States. doi:10.1063/1.874011.
Baylor, L. R., Jernigan, T. C., Combs, S. K., Houlberg, W. A., Murakami, M., Gohil, P., Burrell, K. H., Greenfield, C. M., Groebner, R. J., and Hsieh, C.-L. Mon . "Improved core fueling with high field side pellet injection in the DIII-D tokamak". United States. doi:10.1063/1.874011.
@article{osti_20216056,
title = {Improved core fueling with high field side pellet injection in the DIII-D tokamak},
author = {Baylor, L. R. and Jernigan, T. C. and Combs, S. K. and Houlberg, W. A. and Murakami, M. and Gohil, P. and Burrell, K. H. and Greenfield, C. M. and Groebner, R. J. and Hsieh, C.-L.},
abstractNote = {The capability to inject deuterium pellets from the magnetic high field side (HFS) has been added to the DIII-D tokamak [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)]. It is observed that pellets injected from the HFS lead to deeper mass deposition than identical pellets injected from the outside midplane, in spite of a factor of 4 lower pellet speed. HFS injected pellets have been used to generate peaked density profile plasmas [peaking factor (n{sub e}(0)/<n{sub e}>) in excess of 3] that develop internal transport barriers when centrally heated with neutral beam injection. The transport barriers are formed in conditions where T{sub e}{approx}T{sub i} and q(0) is above unity. The peaked density profiles, characteristic of the internal transport barrier, persist for several energy confinement times. The pellets are also used to investigate transport barrier physics and modify plasma edge conditions. Transitions from L- to H-mode have been triggered by pellets, effectively lowering the H-mode threshold power by 2.4 MW. Pellets injected into H-mode plasmas are found to trigger edge localized modes (ELMs). ELMs triggered from the low field side (LFS) outside midplane injected pellets are of significantly longer duration than from HFS injected pellets. (c) 2000 American Institute of Physics.},
doi = {10.1063/1.874011},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 5,
volume = 7,
place = {United States},
year = {2000},
month = {5}
}