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

Paz-Soldan, C.; Chrystal, C.; Lunia, P.; Nelson, A. O.; Thome, K. E.; Austin, M. E.; Cote, T. B.; Hyatt, A. W.; Leuthold, N.; Marinoni, A.; Osborne, T. H.; Pharr, M.; Sauter, O.; Scotti, F.; Wilks, T. M.; Wilson, H. S.

doi:10.1088/1741-4326/ad69a4

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

Journal Article · 12 August 2024 · Nuclear Fusion

DOI: https://doi.org/10.1088/1741-4326/ad69a4 · OSTI ID:2429056

;

; Hyatt, A. W.;

; Marinoni, A.;

;

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.

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

Grant/Contract Number:: FC02-04ER54698

OSTI ID:: 2429056

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 9 Vol. 64; ISSN 0029-5515

Publisher:: IOP PublishingCopyright Statement

Country of Publication:: IAEA

Language:: English

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