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Simultaneous access to high normalized density, current, pressure, and confinement in strongly-shaped diverted negative triangularity plasmas

Authors :
C. Paz-Soldan
C. Chrystal
P. Lunia
A.O. Nelson
K.E. Thome
M.E. Austin
T.B. Cote
A.W. Hyatt
N. Leuthold
A. Marinoni
T.H. Osborne
M. Pharr
O. Sauter
F. Scotti
T.M. Wilks
H.S. Wilson
Source :
Nuclear Fusion, Vol 64, Iss 9, p 094002 (2024)
Publication Year :
2024
Publisher :
IOP Publishing, 2024.

Abstract

Strongly-shaped diverted negative triangularity (NT) plasmas in the DIII-D tokamak demonstrate simultaneous access to high normalized density, current, pressure, and confinement. NT plasmas are shown to exist across an expansive parameter space compatible with high fusion power production, revealing surprisingly good core stability properties that compare favorably to conventional positive triangularity plasmas in DIII-D. Non-dimensionalizing the key parameters, expanded operating spaces featuring edge safety factors below 3, normalized betas above 3, Greenwald density fractions above 1, and high-confinement mode (H-mode) confinement qualities above 1 are observed, even simultaneously, and all with a robustly stable edge free from deleterious edge-localized mode instabilities. Scaling of the confinement time with engineering parameters reveals at least a linear dependence on plasma current although with significant power degradation, both in excess of expected H-mode scalings. These results increase confidence that NT plasmas are a viable approach to realize fusion power and open directions for future detailed study.

Details

Language :
English
ISSN :
17414326 and 00295515
Volume :
64
Issue :
9
Database :
Directory of Open Access Journals
Journal :
Nuclear Fusion
Publication Type :
Academic Journal
Accession number :
edsdoj.2e8320b464af4043a0dc15372862b64b
Document Type :
article
Full Text :
https://doi.org/10.1088/1741-4326/ad69a4