Lower hybrid experiments at the 1 MW level on Alcator C: heating and current drive
Lower hybrid current drive and heating experiments have been carried out on the Alcator C tokamak at power levels up to 1.15 MW in the density range 1.0 x 10/sup 13/ less than or equal to anti n/sub e/(cm/sup -3/) less than or equal to 1.0 x 10/sup 14/. By launching waves with 67/sup 0/, 90/sup 0/ or 112/sup 0/ phasing of adjacent waveguides, maximum flat-top current drive efficiencies of eta = R(m) x n(10/sup 14/cm/sup -3/)I(MA)/P(MW) = 0.12 at B = 10 tesla, and eta approx. = 0.08 at B = 8 tesla were obtained with molybdenum limiters. With graphite, or silicon-carbide coated graphite limiters the efficiencies were 30 to 40% lower. Current ramping experiments have also been carried out at densities up to anti n approx. = 6 x 10/sup 13/cm/sup -3/. By phasing the adjacent waveguides at 180/sup 0/, heating experiments were performed in the density range 8 x 10/sup 13/ less than or equal to anti n(cm/sup -3/) less than or equal to 2 x 10/sup 14/ in both hydrogen and deuterium plasmas. This range of densities corresponds to the electron Landau heating mode. Using molybdenum limiters, typical heating rates of the order of eta/sub H/ = delta ..sigma.. n/sub j/T/sub j//P/sub rf/ approx. = 10 eV/kW 10/sup 13/cm/sup -3/ were obtained, whereas with the SiC coated graphite limiters heating rates up to eta/sub H/ approx. = 22 were achieved. Measurements of soft and hard x-rays indicate the presence of substantial electron tails in both the current drive and the electron heating regimes. A combined transport, ray-tracing and Fokker-Planck code is used to analyze and model both the heating and the current drive results.
- Research Organization:
- Massachusetts Inst. of Tech., Cambridge (USA). Plasma Fusion Center
- DOE Contract Number:
- AC02-78ET51013
- OSTI ID:
- 7129692
- Report Number(s):
- DOE/ET/51013-121; PFC/CP-84-7; CONF-840311-11; ON: DE84010586
- Resource Relation:
- Conference: 4. international symposium on heating in toroidal plasmas, Rome, Italy, 21 Mar 1984
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALCATOR DEVICE
CURRENT-DRIVE HEATING
LOWER HYBRID HEATING
GRAPHITE
LIMITERS
MICROWAVE EQUIPMENT
MOLYBDENUM
PLASMA DENSITY
SILICON CARBIDES
X RADIATION
CARBIDES
CARBON
CARBON COMPOUNDS
CLOSED PLASMA DEVICES
ELECTRIC HEATING
ELECTROMAGNETIC RADIATION
ELECTRONIC EQUIPMENT
ELEMENTAL MINERALS
ELEMENTS
EQUIPMENT
HEATING
HIGH-FREQUENCY HEATING
IONIZING RADIATIONS
JOULE HEATING
METALS
MINERALS
NONMETALS
PLASMA HEATING
RADIATIONS
RESISTANCE HEATING
SILICON COMPOUNDS
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TRANSITION ELEMENTS
700101* - Fusion Energy- Plasma Research- Confinement
Heating
& Production