Production of high density plasma by pellet injection in TFTR
High plasma densities have been produced in ohmic and neutral beam heated discharges on TFTR using a repeating pneumatic pellet injector developed at Oak Ridge National Laboratory (ORNL). Line average plasma densities as high as 1 x 10/sup 14/ cm/sup -3/ have been attained by injection of five 2.7 mm deuterium pellets ..delta..n/sub e/ = 2 x 10/sup 14/ cm/sup -3/ over a one-second interval into a stetched neutral beam pulse. Injection of a single large (4 mm) pellet in ohmic discharge has produced highly peaked profiles with nec(o) = 1.8 x 10/sup 14/ cm/sup -3/, n/sub e/(0) tau/sub E/(a) = 6.7 x 10/sup 13/ cm/sup -3/ and n/sub D/(0)Ti(0)tau/sub E/(a) = 8.8 x 10/sup 13/ cm/sup -3/ sKeV. Global confinement in these discharges approaches 0.45 seconds with a central density decay time of 2 seconds. Based on a neoclassical resistivity model and x-ray pulse-height analysis, zeff is <2 in both ohmic and beam-heated plasmas. The energy confinement properties of intermediate density (n/sub e/ (0) = 1 x 10/sup 14/ cm/sup -3/) full beam power (5.7 MW, 80 KVD/sup 0/) discharge have been studied in detail using the TRANSP code. Although the global energy confinement (approx. =2 oums at IP = 2.2 MA) is comparable to gas-fueled discharges, the confinement in the central core is considerably longer and electron heat conduction losses are smaller.
- Research Organization:
- Oak Ridge National Lab., TN (USA); Princeton Univ., NJ (USA). Plasma Physics Lab.
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5425517
- Report Number(s):
- CONF-8510266-5; ON: DE86014027
- Resource Relation:
- Conference: International pellet fueling workshop, La Jolla, CA, USA, 30 Oct 1985; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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X-RAY SPECTRA
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PHYSICAL PROPERTIES
SPECTRA
THERMONUCLEAR REACTORS
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