VUV study of impurity generation during ICRF heating experiments on the Alcator C tokamak

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:7018734

Manning, Jr, H L

A 2.2 m grazing incidence VUV monochromator was converted into a time resolving spectrograph by the addition of a new detector system, based on a microchannel plate image intensifier linked to a 1024-element linear photodiode array. The system covers the wavelength range 15 to 1200 A (typically 40 A at a time) with resolution of up to 0.3 A FWHM. Time resolution is selectable down to 0.5 msec. The system sensitivity was absolutely calibrated below 150 A by a soft X-ray calibration facility. The spectrograph was installed on the Alcator C tokamak at MIT to monitor plasma impurity emission. There, cross-calibration with a calibrated EUV monochromator was performed above 400 A. Calibration results, system performance characteristics, and data from Alcator C are presented. Observations of impurity behavior are presented from a series of ICRF heating experiments (180 MHz, 50-400 kW) performed on the Alcator C tokamak, using graphite limiters and stainless steel antenna Faraday shields. Large increases in metal impurity levels were seen during the RF pulse, with iron increasing by a factor of 12 at the highest RF powers. Much similar increases in carbon and oxygen were seen. Potential impurity sources and release mechanisms are discussed.

• Research Organization: Harvard Univ., Boston, MA (USA)
• OSTI ID: 7018734
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101* -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
700102 -- Fusion Energy-- Plasma Research-- Diagnostics
ALCATOR DEVICE
CARBON
CLOSED PLASMA DEVICES
ELECTROMAGNETIC RADIATION
ELEMENTS
FAR ULTRAVIOLET RADIATION
HEATING
HIGH-FREQUENCY HEATING
ICR HEATING
IMPURITIES
IRON
METALS
NONMETALS
OXYGEN
PLASMA HEATING
RADIATIONS
SPECTRA
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
TRANSITION ELEMENTS
ULTRAVIOLET RADIATION
ULTRAVIOLET SPECTRA