Recycling perturbations of supershot plasmas

Conference · Mon Mar 01 00:00:00 EST 1993

OSTI ID:6546215

Scott, S D; McCune, D C; Bell, M G; Bell, R; Budny, R V; Fredrickson, E; Grek, B; Hill, K W; Jassby, D; Jobes, F; Johnson, D W; Johnson, L C; Mansfield, H K; Park, H K; Ramsey, A T; Stratton, B E; Synakowski, E J; Taylor, G; Towner, H H; Zarnstorff, M C ^[1] ; Snipes, J A ^[2]

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1. Princeton Univ., NJ (United States). Plasma Physics Lab.
2. Massachusetts Inst. of Tech., Cambridge, MA (United States)

Thermal heat transport in the core (r/a [le] 0.5) of beam-heated TFTR plasmas vanes by more than a factor of five between L-mode and supershot plasmas for the same I[sub p], B[sub T], and P[sub b]. Operationally, this variation is strongly correlated with the particle recycling coefficient of the carbon-carbon composite inner bumper limiter. The mechanisms underlying this correlation are not understood. This paper describes studies of the edge ion temperature, which is an important parameter if [tau][sub E] is controlled by ion temperature gradient driven turbulence. We find that a edge electron temperature scales simply with power per electron, irrespective of the recycling state of the limiter. By contrast, the scaling of edge ion temperature is strongly affected by the recycling state of the limiter. Much higher edge ion temperatures are attained in low-recycling plasmas for the same power per particle. In addition, perturbative studies of recycling effects on transport have been carried out by puffing in large amounts of helium into a supershot plasma. The local core transport coefficients increase on a transport time scale ([approximately]100 ms), much faster than the current relaxation time scale. This suggests that the current profile is not responsible for the favorable energy confinement of supershot plasmas relative to L-mode plasmas.

• Research Organization: Princeton Univ., NJ (United States). Plasma Physics Lab.
• Sponsoring Organization: USDOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 6546215
• Report Number(s): PPPL-2880; CONF-9206247-3; ON: DE93011493
• Resource Relation: Conference: 19. European Physical Society (EPS) conference on controlled fusion and plasma physics, Innsbruck (Austria), 29 Jun - 4 Jul 1992
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
BEAM INJECTION HEATING
HEAT TRANSFER
TFTR TOKAMAK
H-MODE PLASMA CONFINEMENT
ION TEMPERATURE
TEMPERATURE GRADIENTS
TIME DEPENDENCE
CLOSED PLASMA DEVICES
CONFINEMENT
ENERGY TRANSFER
HEATING
PLASMA CONFINEMENT
PLASMA HEATING
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
700350* - Plasma Production
Heating
Current Drive
& Interactions- (1992-)
700330 - Plasma Kinetics
Transport
& Impurities- (1992-)