2548 K
55 pp.
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TitleA Spectroscopic Study of Impurity Behavior in Neutral-beam and Ohmically Heated TFTR Discharges
Author(s)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.
Publication DateFebruary 1987
Report NumberPPPL-2410
Unique IdentifierACC0138
Other NumbersLegacy ID: DE87008073; OSTI ID: 6919235
Research OrgPrinceton Univ., NJ (USA). Princeton Plasma Physics Laboratory (PPPL)
Contract NoAC02-76CH03073
Sponsoring OrgU. S. Department of Energy (USDOE)
Subject700103 -- Fusion Energy -- Plasma Research -- Kinetics; TFTR Tokamak -- Impurities; Carbon Ions; Energy Losses; Graphite; Joule Heating; Limiters; Neutral Atom Beam Injection; Oxygen Ions; Plasma Density; Spectroscopy
KeywordsBeam Injection; Carbon; Charged Particles; Electric Heating; Elemental Minerals; Elements; Heating; Ions; Losses; Minerals; Nonmetals; Plasma Heating; Resistance Heating; Thermonuclear Reactors; Tokamak Type Reactors
Related Web PagesRussell Hulse, the First Binary Pulsar, and Science Education
AbstractQuantitative 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.
2548 K
55 pp.
View Document 

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