Rotational and magnetic shear stabilization of magnetohydrodynamic modes and turbulence in DIII‐D high performance discharges

the DIII‐D Team

doi:10.1063/1.871991

Rotational and magnetic shear stabilization of magnetohydrodynamic modes and turbulence in DIII‐D high performance discharges

the DIII‐D Team

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126 Scopus citations

Abstract

The confinement and the stability properties of the DIII‐D tokamak [Plasma Physics and Controlled Nuclear Fusion Research 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. 1, p. 159] high‐performance discharges are evaluated in terms of rotational and magnetic shear, with an emphasis on the recent experimental results obtained from the negative central magnetic shear (NCS) experiments. In NCS discharges, a core transport barrier is often observed to form inside the NCS region accompanied by a reduction in core fluctuation amplitudes. Increasing negative magnetic shear contributes to the formation of this core transport barrier, but by itself is not sufficient to fully stabilize the toroidal drift mode (trapped‐electron‐η_i mode) to explain this formation. Comparison of the Doppler shift shear rate to the growth rate of the η_i mode suggests that the large core E×B flow shear can stabilize this mode and broaden the region of reduced core transport. Ideal and resistive stability analysis indicates the performance of NCS discharges with strongly peaked pressure profiles is limited by the resistive interchange mode to low β_N≤2.3. This mode is insensitive to the details of the rotational and the magnetic shear profiles. A new class of discharges, which has a broad region of weak or slightly negative magnetic shear (WNS), is described. The WNS discharges have broader pressure profiles and higher β values than the NCS discharges, together with high confinement and high fusion reactivity.

Original language	English
Pages (from-to)	1951-1958
Number of pages	8
Journal	Physics of Plasmas
Volume	3
Issue number	5
DOIs	https://doi.org/10.1063/1.871991
State	Published - May 1996
Externally published	Yes

Keywords

DOPPLER EFFECT
DOUBLET−3 DEVICE
DRIFT INSTABILITY
HIGH−BETA PLASMA
SHEAR
STABILIZATION
THERMONUCLEAR REACTORS
TURBULENCE

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1063/1.871991

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@article{5d35450b79f54a1ea9dbcfa3caaaa827,

title = "Rotational and magnetic shear stabilization of magnetohydrodynamic modes and turbulence in DIII‐D high performance discharges",

abstract = "The confinement and the stability properties of the DIII‐D tokamak [Plasma Physics and Controlled Nuclear Fusion Research 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. 1, p. 159] high‐performance discharges are evaluated in terms of rotational and magnetic shear, with an emphasis on the recent experimental results obtained from the negative central magnetic shear (NCS) experiments. In NCS discharges, a core transport barrier is often observed to form inside the NCS region accompanied by a reduction in core fluctuation amplitudes. Increasing negative magnetic shear contributes to the formation of this core transport barrier, but by itself is not sufficient to fully stabilize the toroidal drift mode (trapped‐electron‐ηi mode) to explain this formation. Comparison of the Doppler shift shear rate to the growth rate of the ηi mode suggests that the large core E×B flow shear can stabilize this mode and broaden the region of reduced core transport. Ideal and resistive stability analysis indicates the performance of NCS discharges with strongly peaked pressure profiles is limited by the resistive interchange mode to low βN≤2.3. This mode is insensitive to the details of the rotational and the magnetic shear profiles. A new class of discharges, which has a broad region of weak or slightly negative magnetic shear (WNS), is described. The WNS discharges have broader pressure profiles and higher β values than the NCS discharges, together with high confinement and high fusion reactivity.",

keywords = "DOPPLER EFFECT, DOUBLET−3 DEVICE, DRIFT INSTABILITY, HIGH−BETA PLASMA, SHEAR, STABILIZATION, THERMONUCLEAR REACTORS, TURBULENCE",

author = "{the DIII‐D Team} and Lao, {L. L.} and Burrell, {K. H.} and Casper, {T. S.} and Chan, {V. S.} and Chu, {M. S.} and Deboo, {J. C.} and Doyle, {E. J.} and Durst, {R. D.} and Forest, {C. B.} and Greenfield, {C. M.} 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 Q. Peng and Rettig, {C. L.} and G. Rewoldt and Rhodes, {T. L.} and Rice, {B. W.} and Schissel, {D. P.} and Stallard, {B. W.} and Strait, {E. J.} and Tang, {W. M.} and Taylor, {T. S.} and Turnbull, {A. D.} and Waltz, {R. E.}",

year = "1996",

month = may,

doi = "10.1063/1.871991",

language = "English",

volume = "3",

pages = "1951--1958",

journal = "Physics of Plasmas",

issn = "1070-664X",

publisher = "American Institute of Physics",

number = "5",

}

TY - JOUR

T1 - Rotational and magnetic shear stabilization of magnetohydrodynamic modes and turbulence in DIII‐D high performance discharges

AU - the DIII‐D Team

AU - Lao, L. L.

AU - Burrell, K. H.

AU - Casper, T. S.

AU - Chan, V. S.

AU - Chu, M. S.

AU - Deboo, J. C.

AU - Doyle, E. J.

AU - Durst, R. D.

AU - Forest, C. B.

AU - Greenfield, C. M.

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 - Peng, Q.

AU - Rettig, C. L.

AU - Rewoldt, G.

AU - Rhodes, T. L.

AU - Rice, B. W.

AU - Schissel, D. P.

AU - Stallard, B. W.

AU - Strait, E. J.

AU - Tang, W. M.

AU - Taylor, T. S.

AU - Turnbull, A. D.

AU - Waltz, R. E.

PY - 1996/5

Y1 - 1996/5

N2 - The confinement and the stability properties of the DIII‐D tokamak [Plasma Physics and Controlled Nuclear Fusion Research 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. 1, p. 159] high‐performance discharges are evaluated in terms of rotational and magnetic shear, with an emphasis on the recent experimental results obtained from the negative central magnetic shear (NCS) experiments. In NCS discharges, a core transport barrier is often observed to form inside the NCS region accompanied by a reduction in core fluctuation amplitudes. Increasing negative magnetic shear contributes to the formation of this core transport barrier, but by itself is not sufficient to fully stabilize the toroidal drift mode (trapped‐electron‐ηi mode) to explain this formation. Comparison of the Doppler shift shear rate to the growth rate of the ηi mode suggests that the large core E×B flow shear can stabilize this mode and broaden the region of reduced core transport. Ideal and resistive stability analysis indicates the performance of NCS discharges with strongly peaked pressure profiles is limited by the resistive interchange mode to low βN≤2.3. This mode is insensitive to the details of the rotational and the magnetic shear profiles. A new class of discharges, which has a broad region of weak or slightly negative magnetic shear (WNS), is described. The WNS discharges have broader pressure profiles and higher β values than the NCS discharges, together with high confinement and high fusion reactivity.

AB - The confinement and the stability properties of the DIII‐D tokamak [Plasma Physics and Controlled Nuclear Fusion Research 1986 (International Atomic Energy Agency, Vienna, 1987), Vol. 1, p. 159] high‐performance discharges are evaluated in terms of rotational and magnetic shear, with an emphasis on the recent experimental results obtained from the negative central magnetic shear (NCS) experiments. In NCS discharges, a core transport barrier is often observed to form inside the NCS region accompanied by a reduction in core fluctuation amplitudes. Increasing negative magnetic shear contributes to the formation of this core transport barrier, but by itself is not sufficient to fully stabilize the toroidal drift mode (trapped‐electron‐ηi mode) to explain this formation. Comparison of the Doppler shift shear rate to the growth rate of the ηi mode suggests that the large core E×B flow shear can stabilize this mode and broaden the region of reduced core transport. Ideal and resistive stability analysis indicates the performance of NCS discharges with strongly peaked pressure profiles is limited by the resistive interchange mode to low βN≤2.3. This mode is insensitive to the details of the rotational and the magnetic shear profiles. A new class of discharges, which has a broad region of weak or slightly negative magnetic shear (WNS), is described. The WNS discharges have broader pressure profiles and higher β values than the NCS discharges, together with high confinement and high fusion reactivity.

KW - DOPPLER EFFECT

KW - DOUBLET−3 DEVICE

KW - DRIFT INSTABILITY

KW - HIGH−BETA PLASMA

KW - SHEAR

KW - STABILIZATION

KW - THERMONUCLEAR REACTORS

KW - TURBULENCE

UR - http://www.scopus.com/inward/record.url?scp=22244445355&partnerID=8YFLogxK

U2 - 10.1063/1.871991

DO - 10.1063/1.871991

M3 - Article

AN - SCOPUS:22244445355

SN - 1070-664X

VL - 3

SP - 1951

EP - 1958

JO - Physics of Plasmas

JF - Physics of Plasmas

IS - 5

ER -

Rotational and magnetic shear stabilization of magnetohydrodynamic modes and turbulence in DIII‐D high performance discharges

Abstract

Keywords

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