Results obtained using the pellet charge exchange diagnostic on TFTR

Journal Article · Sun Jan 01 00:00:00 EST 1995 · Review of Scientific Instruments; (United States)

DOI:https://doi.org/10.1063/1.1146408· OSTI ID:7060092

McChesney, J M; Duong, H H; Fisher, R K; Khudoleev, A V; Mansfield, D K; Medley, S S; Parks, P B; Petrov, M P; Roquemore, A L ^[1]

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1. General Atomics, San Diego, California 92186-9784 (United States)

Experiments are underway on TFTR to measure the confined alpha particle distribution functions using small low-[ital Z] pellets injected into the plasma [Fisher [ital et] [ital al]. Fusion Technol. [bold 13], 536 (1988)]. Upon entering the plasma, the pellet ablates, forming a plasma ablation cloud, elongated in the magnetic field direction, that travels alongside the pellet. A small fraction of the fusion produced 3.5 MeV alpha particles incident on the cloud are converted to helium neutrals. By measuring the resultant helium neutrals escaping from the plasma by means of a mass and energy resolving charge exchange analyzer, the energy distribution of the alpha particles incident on the cloud can be inferred. Preliminary experiments to observe neutrals from the 100 to 1000 keV [sup 3]He tail produced during ICRF minority heating experiments were successful. However, no significant alpha particle signals have been observed during D-T operation on TFTR. We attribute this lack of signal to stochastic toroidal field ripple loss in the outer regions of the plasma. We are studying ways to improve the pellet penetration so that the pellet penetrates into the central regions of the plasma where ripple induced losses are small and the alpha population is high.

• DOE Contract Number: FG03-92ER54150; AC02-76CH03073
• OSTI ID: 7060092
• Journal Information: Review of Scientific Instruments; (United States), Vol. 66:1; ISSN 0034-6748
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
PLASMA DIAGNOSTICS
PELLET INJECTION
TFTR TOKAMAK
ALPHA SPECTRA
ABLATION
CHARGE-EXCHANGE REACTIONS
DISTRIBUTION FUNCTIONS
HELIUM 3
CLOSED PLASMA DEVICES
EVEN-ODD NUCLEI
FUNCTIONS
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
NUCLEAR REACTIONS
NUCLEI
SPECTRA
STABLE ISOTOPES
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
700320* - Plasma Diagnostic Techniques & Instrumentation- (1992-)
700410 - Specific Fusion Devices & Experiments- (1992-)