Lower-hybrid-heating experiments on the Alcator C and the Versator II tokamaks

Conference · Fri Jan 01 04:00:00 EST 1982

OSTI ID:5259675

Takase, Y.

Initial results are reported from lower hybrid wave heating experiments carried out on the MIT Alcator C and Versator II tokamaks. In the Alcator C experiments a 4 waveguide array, with internally brazed ceramic windows has been used to inject 160 kW of microwave power at 4.6 GHz into the plasma with n/sub 0/ less than or equal to 1 x 10/sup 15/ cm/sup -3/, and B/sub 0/ less than or equal to 12 T. An RF power density of 8 kW/cm/sup 2/ has been transmitted into the plasma without RF breakdown. RF coupling studies show optimal coupling (R less than or equal to 10%) when the local density at the waveguide mouth is 25 to 50 times overdense. Initial heating experiments show an ion tail formation in hydrogen discharge peaking at a density of anti n approx. = 2.7 x 10/sup 14/ cm/sup -3/ at B = 8.9 T, and bulk ion heating at a density of anti n approx. = 1.5 x 10/sup 14/ c/sup -3/ at B approx. = 11 T. Evidence of RF current enhancement has been observed at a density of n approx. = 3 x 10/sup 13/ cm/sup -3/. In the Versator II tokamak initial ion heating studies have been carried out using an 800 MHz, 140 kW klystron. With 50 kW of net RF power injected through a 4 waveguide grill at B = 1.3 T and anti n = 2.5 x 10/sup 13/ cm/sup -3/, Doppler broadening of the OVII and NVI lines shows a ..delta..T/sub i/ = 50 eV rise in the bulk ion temperature. A significant RF produced ion tail is also observed by charge exchange analysis. We have succeeded in combining a toroidal ray-tracing code and a 1-D transport code to study the heating density bands and heating efficiencies.

• Research Organization: Massachusetts Institute of Technology, Cambridge, Ma.
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-78ET51013
• OSTI ID: 5259675
• Report Number(s): DOE/ET/51013-41; PFC/CP-82-5; CONF-820345-10; ON: DE82013674
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101* -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
ALCATOR DEVICE
CLOSED PLASMA DEVICES
ELECTROMAGNETIC RADIATION
HEATING
HIGH-FREQUENCY HEATING
HYBRID RESONANCE
ION TEMPERATURE
MICROWAVE RADIATION
PLASMA HEATING
RADIATIONS
RESONANCE
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TRANSPORT THEORY