Characteristics of the First H-mode Discharges in NSTX

Technical Report · Thu May 10 00:00:00 EDT 2001

DOI:https://doi.org/10.2172/784549· OSTI ID:784549

Maingi, R; Bell, M G; Bell, R E; Bush, C E; Fredrickson, E D; Gates, D A; Kaye, S M; Kugel, H W; LeBlanc, B P; Menard, J E; Mueller, D; Sabbagh, S A; Stutman, D; Taylor, G; Johnson, D W; Kaita, R; Maqueda, R J; Ono, M; Paoletti, F; Peng, Y-K M ; Roquemore, A L; Skinner, C H; Soukhanovskii, V A; and Synakowski, E J

We report observations of the first low-to-high (L-H) confinement mode transitions in the National Spherical Torus Experiment (NSTX). The H-mode energy confinement time increased over reference L-mode discharges transiently by 100-300%, as high as {approximately}150 ms. This confinement time is {approximately}1.8-2.3 times higher than predicted by a multi-machine ELM-free H-mode scaling. This achievement extends the H-mode window of fusion devices down to a record low aspect ratio (R/a) {approximately} 1.3, challenging both confinement and L-H power thresholds scalings based on conventional aspect ratio tokamaks.

• Research Organization: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
• Sponsoring Organization: USDOE Office of Energy Research (ER) (US)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 784549
• Report Number(s): PPPL-3563; TRN: US0106114
• Resource Relation: Other Information: PBD: 10 May 2001
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
NSTX DEVICE
H-MODE PLASMA CONFINEMENT
ASPECT RATIO
L-MODE PLASMA CONFINEMENT
MODE CONVERSION
CONFINEMENT TIME