Gas puff fueled H-mode discharges with good energy confinement above the Greenwald density limit on DIII-D

T. H. Osborne; M. A. Mahdavi; M. Chu; M. E. Fenstermacher; R. La Haye; A. W. Leonard; G. McKee; T. W. Petrie; C. Rettig; M. Wade; J. Watkins

doi:10.1016/S0022-3115(00)00660-7

Gas puff fueled H-mode discharges with good energy confinement above the Greenwald density limit on DIII-D

T. H. Osborne, M. A. Mahdavi, M. Chu, M. E. Fenstermacher, R. La Haye, A. W. Leonard, G. McKee, T. W. Petrie, C. Rettig, M. Wade, J. Watkins

Research output: Contribution to journal › Article › peer-review

20 Scopus citations

Abstract

Tokamak discharges with electron densities as high as 1.4 times the Greenwald density, and good energy confinement, H_ITER89P = 1.9, were obtained with D₂ gas puffing on DIII-D. The divertor configuration of these discharges, low triangularity with pumping of the private flux region, was important in avoiding a transition to the L-mode or Type III ELM regimes in which energy confinement was reduced. Although these discharges show a decrease in H-mode pedestal energy at high density through reduction in the edge pressure gradient, peaking of the density profile compensated for the effect of this decrease on the overall stored energy. Spontaneous density profile peaking occurred under conditions which enhance the neoclassical Ware pinch. The high density phase was terminated by an internal MHD event that has the characteristics of a neoclassical tearing mode.

Original language	English
Pages (from-to)	1013-1017
Number of pages	5
Journal	Journal of Nuclear Materials
Volume	290-293
DOIs	https://doi.org/10.1016/S0022-3115(00)00660-7
State	Published - Mar 2001
Externally published	Yes

Funding

Work supported by US DOE under Contract Nos. DE-AC03-99ER54463, DE-AC04-94AL85000, and W-7405-ENG-48.

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10.1016/S0022-3115(00)00660-7

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@article{36e969d0ec364d43a4aaa0fde2406688,

title = "Gas puff fueled H-mode discharges with good energy confinement above the Greenwald density limit on DIII-D",

abstract = "Tokamak discharges with electron densities as high as 1.4 times the Greenwald density, and good energy confinement, HITER89P = 1.9, were obtained with D2 gas puffing on DIII-D. The divertor configuration of these discharges, low triangularity with pumping of the private flux region, was important in avoiding a transition to the L-mode or Type III ELM regimes in which energy confinement was reduced. Although these discharges show a decrease in H-mode pedestal energy at high density through reduction in the edge pressure gradient, peaking of the density profile compensated for the effect of this decrease on the overall stored energy. Spontaneous density profile peaking occurred under conditions which enhance the neoclassical Ware pinch. The high density phase was terminated by an internal MHD event that has the characteristics of a neoclassical tearing mode.",

author = "Osborne, {T. H.} and Mahdavi, {M. A.} and M. Chu and Fenstermacher, {M. E.} and {La Haye}, R. and Leonard, {A. W.} and G. McKee and Petrie, {T. W.} and C. Rettig and M. Wade and J. Watkins",

year = "2001",

month = mar,

doi = "10.1016/S0022-3115(00)00660-7",

language = "English",

volume = "290-293",

pages = "1013--1017",

journal = "Journal of Nuclear Materials",

issn = "0022-3115",

publisher = "Elsevier",

}

TY - JOUR

T1 - Gas puff fueled H-mode discharges with good energy confinement above the Greenwald density limit on DIII-D

AU - Osborne, T. H.

AU - Mahdavi, M. A.

AU - Chu, M.

AU - Fenstermacher, M. E.

AU - La Haye, R.

AU - Leonard, A. W.

AU - McKee, G.

AU - Petrie, T. W.

AU - Rettig, C.

AU - Wade, M.

AU - Watkins, J.

PY - 2001/3

Y1 - 2001/3

N2 - Tokamak discharges with electron densities as high as 1.4 times the Greenwald density, and good energy confinement, HITER89P = 1.9, were obtained with D2 gas puffing on DIII-D. The divertor configuration of these discharges, low triangularity with pumping of the private flux region, was important in avoiding a transition to the L-mode or Type III ELM regimes in which energy confinement was reduced. Although these discharges show a decrease in H-mode pedestal energy at high density through reduction in the edge pressure gradient, peaking of the density profile compensated for the effect of this decrease on the overall stored energy. Spontaneous density profile peaking occurred under conditions which enhance the neoclassical Ware pinch. The high density phase was terminated by an internal MHD event that has the characteristics of a neoclassical tearing mode.

AB - Tokamak discharges with electron densities as high as 1.4 times the Greenwald density, and good energy confinement, HITER89P = 1.9, were obtained with D2 gas puffing on DIII-D. The divertor configuration of these discharges, low triangularity with pumping of the private flux region, was important in avoiding a transition to the L-mode or Type III ELM regimes in which energy confinement was reduced. Although these discharges show a decrease in H-mode pedestal energy at high density through reduction in the edge pressure gradient, peaking of the density profile compensated for the effect of this decrease on the overall stored energy. Spontaneous density profile peaking occurred under conditions which enhance the neoclassical Ware pinch. The high density phase was terminated by an internal MHD event that has the characteristics of a neoclassical tearing mode.

UR - http://www.scopus.com/inward/record.url?scp=0035277158&partnerID=8YFLogxK

U2 - 10.1016/S0022-3115(00)00660-7

DO - 10.1016/S0022-3115(00)00660-7

M3 - Article

AN - SCOPUS:0035277158

SN - 0022-3115

VL - 290-293

SP - 1013

EP - 1017

JO - Journal of Nuclear Materials

JF - Journal of Nuclear Materials

ER -

Gas puff fueled H-mode discharges with good energy confinement above the Greenwald density limit on DIII-D

Abstract

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