A spectroscopic study of impurity behavior in neutral-beam and ohmically heated TFTR discharges

Technical Report · Sun Feb 01 00:00:00 EST 1987

DOI:https://doi.org/10.2172/6919235· OSTI ID:6919235

Stratton, B C; Ramsey, A T; Boody, F P; Bush, C E; Fonck, R J; Groenbner, R J; Hulse, R A; Richards, R K; Schivell, J

Quantitative spectroscopic measurements of Z/sub eff/, impurity densities, and radiated power losses have been made for ohmic- and neutral-beam-heated TFTR discharges at a plasma current of 2.2 MA and toroidal field of 4.7 T. Variations in these quantities with line-average plasma density (anti n/sub e/) and beam power up to 5.6 MW are presented for discharges on a graphite movable limiter. A detailed discussion of the use of an impurity transport model to infer absolute impurity densities and radiative losses from line intensity and visible continuum measurements is given. These discharges were dominated by low-Z impurities with carbon having a considerably higher density than oxygen, except in high-anti n/sub e/ ohmic discharges, where the densities of carbon and oxygen were comparable. Metallic impurity concentrations and radiative losses were small, resulting in hollow radiated power profiles and fractions of the input power radiated being 30 to 50% for ohmic heating and 30% or less with beam heating. Spectroscopic estimates of the radiated power were in good agreement with bolometrically measured values. Due to an increase in the carbon density, Z/sub eff/ rose from 2.0 to 2.8 as the beam power increased from 0 to 5.6 MW, pointing to a potentially serious dilution of the neutron-producing plasma ions as the beam power increased. Both the low-Z and metallic impurity concentrations were approximately constant with minor radius, indicating no central impurity accumulation in these discharges.

• Research Organization: Princeton Univ., NJ (USA). Plasma Physics Lab.
• DOE Contract Number: AC02-76CH03073
• OSTI ID: 6919235
• Report Number(s): PPPL-2410; ON: DE87008073
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700103* -- Fusion Energy-- Plasma Research-- Kinetics
BEAM INJECTION
CARBON
CARBON IONS
CHARGED PARTICLES
ELECTRIC HEATING
ELEMENTAL MINERALS
ELEMENTS
ENERGY LOSSES
GRAPHITE
HEATING
IMPURITIES
IONS
JOULE HEATING
LIMITERS
LOSSES
MINERALS
NEUTRAL ATOM BEAM INJECTION
NONMETALS
OXYGEN IONS
PLASMA DENSITY
PLASMA HEATING
RESISTANCE HEATING
SPECTROSCOPY
TFTR TOKAMAK
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS