Confinement studies of neutral beam heated discharges in TFTR

Technical Report · Fri Nov 01 04:00:00 EST 1985

DOI:https://doi.org/10.2172/6415702· OSTI ID:6415702

Murakami, M; Arunasalam, V; Bell, J D; Stauffer, F; Bell, M G; Bitte, M; Blanchard, W R; Boody, F; Britz, N

The TFTR tokamak has reached its original machine design specifications (I/sub p/ = 2.5 MA and B/sub T/ = 5.2T). Recently, the D/sup 0/ neutral beam heating power has been increased to 6.3 MW. By operating at low plasma current (I/sub p/ approx. = 0.8 MA) and low density anti n/sub e/ approx. = 1 x 10/sup 19/m/sup -3/), high ion temperatures (9 +- keV) and rotation speeds (7 x 10/sup 5/ m/s) have been achieved during injection. At the opposite extreme, pellet injection into high current plasmas has been used to increase the line-average density to 8 x 10/sup 19/m/sup -3/ and the central density to 1.6 x 10/sup 20/m/sup -3// This wide range of operating conditions has enabled us to conduct scaling studies of the global energy confinement time in both ohmically and beam heated discharges as well as more detailed transport studies of the profile dependence. In ohmic discharges, the energy confinement time is observed to scale linearly with density only up to anti n/sub e/ approx. 4.5 x 10/sup 19/m/sup -3/ and then to increase more gradually, achieving a maximum value of approx. 0.45 s. In beam heated discharges, the energy confinement time is observed to decrease with beam power and to increase with plasma current. With P/sub b/ = 5.6 MW, anti n/sub e/ = 4.7 x 10/sup 19/m/sup -3/, I/sub p/ = 2.2 MA and B/sub T = 4.7T, the gross energy confinement time is 0.22 s and T/sub i/(0) = 4.8 keV. Despite shallow penetration of D/sup 0/ beams (at the beam energy less than or equal to 80 keV with low species yield), tau/sub E/(a) values are as large as those for H/sup 0/ injection, but central confinement times are substantially greater. This is a consequence of the insensitivity of the temperature and safety factor profile shapes to the heating profile. The radial variation of tau/sub E/ is even more pronounced with D/sup 0/ injection into high density pellet-injected plasmas. 25 refs.

• Research Organization: Oak Ridge National Lab., TN (USA); Maryland Univ., College Park (USA); Wisconsin Univ., Madison (USA); GA Technologies, Inc., San Diego, CA (USA); RCA Corp., Princeton, NJ (USA). David Sanoff Research Center; Princeton Univ., NJ (USA). Plasma Physics Lab.
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 6415702
• Report Number(s): PPPL-2285; ON: DE86005038
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101* -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
BEAM INJECTION
COMPUTER CODES
CONFINEMENT
CONTAINMENT
CONTAINMENT SYSTEMS
DESIGN
ENGINEERED SAFETY SYSTEMS
NEUTRAL ATOM BEAM INJECTION
PLASMA CONFINEMENT
S CODES
SCALING
SPECIFICATIONS
TFTR TOKAMAK
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS