Confinement and stability of DIII-D negative central shear discharges

L. L. Lao; K. H. Burrell; T. S. Casper; V. S. Chan; M. S. Chu; C. B. Forest; R. J. Groebner; F. L. Hinton; Y. Kawano; E. A. Lazarus; Y. R. Lin-Liu; M. E. Mauel; W. H. Meyer; R. L. Miller; G. A. Navratil; T. H. Osborne; C. L. Rettig; G. Rewoldt; B. W. Rice; B. W. Stallard; E. J. Strait; T. S. Taylor; W. M. Tang; A. D. Turnbull; R. E. Waltz

doi:10.1088/0741-3335/38/8/051

Confinement and stability of DIII-D negative central shear discharges

L. L. Lao, K. H. Burrell, T. S. Casper, V. S. Chan, M. S. Chu, C. B. Forest, R. J. Groebner, F. L. Hinton, Y. Kawano, E. A. Lazarus, Y. R. Lin-Liu, M. E. Mauel, W. H. Meyer, R. L. Miller, G. A. Navratil, T. H. Osborne, C. L. Rettig, G. Rewoldt, B. W. Rice, B. W. StallardE. J. Strait, T. S. Taylor, W. M. Tang, A. D. Turnbull, R. E. Waltz

PPPL Computational Science

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Abstract

Negative central magnetic shear (NCS) discharges with β_N ≤ 4, H ≤ 3 and up to 80% of the current non-inductively driven are reproducibly produced in the DIII-D tokamak. Strong peaking of T_i, plasma rotation and, in some cases, n_e are observed inside the NCS region. Transport analysis shows that the core ion thermal diffusivity is substantially reduced and near the neoclassical value after the formation of the internal transport barrier. The negative central shear is necessary but not sufficient for the formation of this transport barrier. The power required for the formation appears to increase with the toroidal magnetic field. The high performance phase of H-mode NCS discharges often ends with an ELM-like collapse initiated from the edge whereas the L-mode discharges which have a more peaked pressure profile tend to end with a more global n = 1 MHD event.

Original language	English (US)
Pages (from-to)	1439-1443
Number of pages	5
Journal	Plasma Physics and Controlled Fusion
Volume	38
Issue number	8
DOIs	https://doi.org/10.1088/0741-3335/38/8/051
State	Published - 1996

All Science Journal Classification (ASJC) codes

Nuclear Energy and Engineering
Condensed Matter Physics

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10.1088/0741-3335/38/8/051

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Lao, L. L., Burrell, K. H., Casper, T. S., Chan, V. S., Chu, M. S., Forest, C. B., Groebner, R. J., Hinton, F. L., Kawano, Y., Lazarus, E. A., Lin-Liu, Y. R., Mauel, M. E., Meyer, W. H., Miller, R. L., Navratil, G. A., Osborne, T. H., Rettig, C. L., Rewoldt, G., Rice, B. W., ... Waltz, R. E. (1996). Confinement and stability of DIII-D negative central shear discharges. Plasma Physics and Controlled Fusion, 38(8), 1439-1443. https://doi.org/10.1088/0741-3335/38/8/051

@article{72865555cfcf4815b2b4030b216dca21,

title = "Confinement and stability of DIII-D negative central shear discharges",

abstract = "Negative central magnetic shear (NCS) discharges with βN ≤ 4, H ≤ 3 and up to 80\% of the current non-inductively driven are reproducibly produced in the DIII-D tokamak. Strong peaking of Ti, plasma rotation and, in some cases, ne are observed inside the NCS region. Transport analysis shows that the core ion thermal diffusivity is substantially reduced and near the neoclassical value after the formation of the internal transport barrier. The negative central shear is necessary but not sufficient for the formation of this transport barrier. The power required for the formation appears to increase with the toroidal magnetic field. The high performance phase of H-mode NCS discharges often ends with an ELM-like collapse initiated from the edge whereas the L-mode discharges which have a more peaked pressure profile tend to end with a more global n = 1 MHD event.",

author = "Lao, \{L. L.\} and Burrell, \{K. H.\} and Casper, \{T. S.\} and Chan, \{V. S.\} and Chu, \{M. S.\} and Forest, \{C. B.\} and Groebner, \{R. J.\} and Hinton, \{F. L.\} and Y. Kawano and Lazarus, \{E. A.\} and Lin-Liu, \{Y. R.\} and Mauel, \{M. E.\} and Meyer, \{W. H.\} and Miller, \{R. L.\} and Navratil, \{G. A.\} and Osborne, \{T. H.\} and Rettig, \{C. L.\} and G. Rewoldt and Rice, \{B. W.\} and Stallard, \{B. W.\} and Strait, \{E. J.\} and Taylor, \{T. S.\} and Tang, \{W. M.\} and Turnbull, \{A. D.\} and Waltz, \{R. E.\}",

year = "1996",

doi = "10.1088/0741-3335/38/8/051",

language = "English (US)",

volume = "38",

pages = "1439--1443",

journal = "Plasma Physics and Controlled Fusion",

issn = "0741-3335",

publisher = "IOP Publishing Ltd.",

number = "8",

}

Lao, LL, Burrell, KH, Casper, TS, Chan, VS, Chu, MS, Forest, CB, Groebner, RJ, Hinton, FL, Kawano, Y, Lazarus, EA, Lin-Liu, YR, Mauel, ME, Meyer, WH, Miller, RL, Navratil, GA, Osborne, TH, Rettig, CL, Rewoldt, G, Rice, BW, Stallard, BW, Strait, EJ, Taylor, TS, Tang, WM, Turnbull, AD & Waltz, RE 1996, 'Confinement and stability of DIII-D negative central shear discharges', Plasma Physics and Controlled Fusion, vol. 38, no. 8, pp. 1439-1443. https://doi.org/10.1088/0741-3335/38/8/051

TY - JOUR

T1 - Confinement and stability of DIII-D negative central shear discharges

AU - Lao, L. L.

AU - Burrell, K. H.

AU - Casper, T. S.

AU - Chan, V. S.

AU - Chu, M. S.

AU - Forest, C. B.

AU - Groebner, R. J.

AU - Hinton, F. L.

AU - Kawano, Y.

AU - Lazarus, E. A.

AU - Lin-Liu, Y. R.

AU - Mauel, M. E.

AU - Meyer, W. H.

AU - Miller, R. L.

AU - Navratil, G. A.

AU - Osborne, T. H.

AU - Rettig, C. L.

AU - Rewoldt, G.

AU - Rice, B. W.

AU - Stallard, B. W.

AU - Strait, E. J.

AU - Taylor, T. S.

AU - Tang, W. M.

AU - Turnbull, A. D.

AU - Waltz, R. E.

PY - 1996

Y1 - 1996

N2 - Negative central magnetic shear (NCS) discharges with βN ≤ 4, H ≤ 3 and up to 80% of the current non-inductively driven are reproducibly produced in the DIII-D tokamak. Strong peaking of Ti, plasma rotation and, in some cases, ne are observed inside the NCS region. Transport analysis shows that the core ion thermal diffusivity is substantially reduced and near the neoclassical value after the formation of the internal transport barrier. The negative central shear is necessary but not sufficient for the formation of this transport barrier. The power required for the formation appears to increase with the toroidal magnetic field. The high performance phase of H-mode NCS discharges often ends with an ELM-like collapse initiated from the edge whereas the L-mode discharges which have a more peaked pressure profile tend to end with a more global n = 1 MHD event.

AB - Negative central magnetic shear (NCS) discharges with βN ≤ 4, H ≤ 3 and up to 80% of the current non-inductively driven are reproducibly produced in the DIII-D tokamak. Strong peaking of Ti, plasma rotation and, in some cases, ne are observed inside the NCS region. Transport analysis shows that the core ion thermal diffusivity is substantially reduced and near the neoclassical value after the formation of the internal transport barrier. The negative central shear is necessary but not sufficient for the formation of this transport barrier. The power required for the formation appears to increase with the toroidal magnetic field. The high performance phase of H-mode NCS discharges often ends with an ELM-like collapse initiated from the edge whereas the L-mode discharges which have a more peaked pressure profile tend to end with a more global n = 1 MHD event.

UR - https://www.scopus.com/pages/publications/0030204432

UR - https://www.scopus.com/inward/citedby.url?scp=0030204432&partnerID=8YFLogxK

U2 - 10.1088/0741-3335/38/8/051

DO - 10.1088/0741-3335/38/8/051

M3 - Article

AN - SCOPUS:0030204432

SN - 0741-3335

VL - 38

SP - 1439

EP - 1443

JO - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

IS - 8

ER -

Confinement and stability of DIII-D negative central shear discharges

Abstract

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