Achievement of reactor-relevant high normalized beta and high confinement with L-mode edge in negative triangularity shape in DIII-D

Austin, M.; Marinoni, A.; Walker, M. L.; Brookman, M. W.; deGrassie, J.; Hyatt, A. W.; McKee, G. R.; Petty, C. C.; Rhodes, T. L.; Smith, S. P.; Sung, C.; Thome, K. E.; Turnbull, A. H.

doi:10.1103/physrevlett.122.115001

Achievement of reactor-relevant high normalized beta and high confinement with L-mode edge in negative triangularity shape in DIII-D

Journal Article · Mon Mar 18 00:00:00 EDT 2019 · Physical Review Letters

DOI:https://doi.org/10.1103/physrevlett.122.115001· OSTI ID:1482806

Austin, M. ^[1]; Marinoni, A. ^[2]; Walker, M. L. ^[3]; Brookman, M. W. ^[3]; deGrassie, J. ^[3]; Hyatt, A. W. ^[3]; McKee, G. R. ^[4]; Petty, C. C. ^[3]; Rhodes, T. L. ^[5]; Smith, S. P. ^[3]; Sung, C. ^[6]; Thome, K. E. ^[3]; Turnbull, A. H. ^[3]

Univ. of Texas-Austin, Austin, TX (United States); General Atomics
MIT Plasma Science and Fusion Center, Cambridge, MA (United States)
General Atomics, San Diego, CA (United States)
Univ. of Wisconsin-Madison, Madison, WI (United States)
Univ. of California-Los Angeles, Los Angeles, CA (United States)
Lam Research Corp., Fremont, CA (United States)

In this paper, plasma discharges with negative triangularity (δ =-0.4) shape have been created in DIII-D with significant normalized beta (ß_N = 2.7) and confinement characteristic of the “high confinement” mode (H_98y2 = 1.2) despite the absence of an edge pressure pedestal and no edge localized modes (ELMs). These inner-walllimited plasmas have similar global performance as a positive triangularity (δ = +0.4) ELMing H-mode discharge with the same plasma current, elongation and cross-sectional area. For cases both of dominant electron cyclotron heating with T_e/T_i > 1 and dominant neutral beam injection heating with T_e/T_i = 1, turbulent fluctuations over radii 0.5 < ρ < 0.9 were reduced in negative triangularity over the matching positive triangularity by 10-50% depending on radius and conditions.

View Accepted Manuscript (DOE)

Research Organization:: General Atomics, San Diego, CA (United States); Univ. of Texas, Austin, TX (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Grant/Contract Number:: FC02-04ER54698; FG02-97ER54415

OSTI ID:: 1482806

Alternate ID(s):: OSTI ID: 1502834
OSTI ID: 1508884

Journal Information:: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 11 Vol. 122; ISSN 0031-9007

Publisher:: American Physical Society (APS)Copyright Statement

Country of Publication:: United States

Language:: English

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H-mode grade confinement in L-mode edge plasmas at negative triangularity on DIII-D Marinoni, A.; Austin, M. E.; Hyatt, A. W. Physics of Plasmas, Vol. 26, Issue 4 https://doi.org/10.1063/1.5091802	journal	April 2019
Turbulent transport in TCV plasmas with positive and negative triangularity Merlo, G.; Fontana, M.; Coda, S. Physics of Plasmas, Vol. 26, Issue 10 https://doi.org/10.1063/1.5115390	journal	October 2019
Computational analysis of ion orbital loss in diverted positive- and negative-triangularity tokamaks Nishimura, Y.; Waelbroeck, F. L.; Zheng, L. J. Physics of Plasmas, Vol. 27, Issue 1 https://doi.org/10.1063/1.5131157	journal	January 2020
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Central ion cyclotron emission in the DIII-D tokamak Thome, K. E.; Pace, D. C.; Pinsker, R. I. Nuclear Fusion, Vol. 59, Issue 8 https://doi.org/10.1088/1741-4326/ab20e7	journal	June 2019
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