Imaging of lithium pellet ablation trails and measurement of q profiles in TFTR

Journal Article · Thu Oct 01 04:00:00 EDT 1992 · Review of Scientific Instruments; (United States)

DOI:https://doi.org/10.1063/1.1143849· OSTI ID:7153778

Terry, J L; Marmar, E S; Snipes, J A; Garnier, D ^[1]; Sergeev, V Y ^[2]

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1. MIT Plasma Fusion Center, Cambridge, Massachusetts 02139 (United States)
2. Technical University, Plasma Physics Department, St. Petersburg, 195251, (Russia) Princeton University, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

Video images with 2 {mu}s exposures of the Li{sup +} emission in Li pellet ablation clouds have been obtained in a variety of Tokamak Fusion Test Reactor tokamak discharges. The pellet clouds are viewed from behind the pellet, which is injected from the outside midplane. In this view, the emission forms an elongated {ital cigar} shape with the long dimension of the cigar aligned with the local magnetic field. In some cases, two distinct parallel cigars can be seen simultaneously, displaced vertically from one another by {similar to}5 cm. Measurements using a ten channel array of position sensitive photodiodes show that the mean position of the ablation cloud emission can oscillate vertically by {similar to}4 cm with periods in the 60--100 {mu}s range, and that these oscillations are highly correlated with bursts'' in the cloud emission. The tilt of the cloud is also measured as a function of time as the pellet traverses the plasma, and in this way the poloidal field profile is obtained. (The total transit time of the pellet is {similar to}1 ms.) Magnetohydrodynamic equilibrium reconstructions of {ital q} profiles have been determined using these measurements.

• DOE Contract Number: FG02-90ER54084; AC02-76CH03073
• OSTI ID: 7153778
• Journal Information: Review of Scientific Instruments; (United States), Journal Name: Review of Scientific Instruments; (United States) Vol. 63:10; ISSN RSINA; ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700320* -- Plasma Diagnostic Techniques & Instrumentation-- (1992-)
ABLATION
ALKALI METALS
CLOSED PLASMA DEVICES
ELEMENTS
EMISSION SPECTRA
IMAGES
LITHIUM
MAGNETIC FIELD CONFIGURATIONS
METALS
PELLET INJECTION
PHOTODIODES
PLASMA DIAGNOSTICS
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
SPECTRA
TFTR TOKAMAK
THERMONUCLEAR DEVICES
TOKAMAK DEVICES