Development and operation of a backward wave oscillator based FIR scattering system for DIII-D
- Institute of Plasma and Fusion Research, University of California, Los Angeles, CA (USA)
The laser-based far-infrared scattering system ({lambda}=1.22 mm) on DIII-D is to be upgraded by the addition of a backward wave oscillator or carcinotron. By supplying up to 300 mW at {lambda}=1.06 mm, the carcinotron is expected to increase the scattered power and signal-to-noise ratio by more than ten times. In addition, the laser has suffered from significant frequency pulling during high density discharges which has necessitated using undesirable geometry to obtain accuracy in the low-frequency part of the fluctuation spectrum. However, the carcinotron-based system will use an IF tracking system to simultaneously remove the excessive phase noise, frequency drift typical of high-frequency tubes, and the effects of frequency pulling. This should allow more reliable measurements of low-frequency asymmetric spectra under all discharge conditions. The local oscillator will be provided by a frequency doubled and locked klystron, to enable heterodyne detection of the scattered signal. Results of extensive laboratory tests of the carcinotron-based scattering apparatus are to be presented.
- DOE Contract Number:
- FG03-86ER53225
- OSTI ID:
- 6134574
- Journal Information:
- Review of Scientific Instruments; (USA), Journal Name: Review of Scientific Instruments; (USA) Vol. 61:10; ISSN RSINA; ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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BACKWARD WAVE TUBES
CLOSED PLASMA DEVICES
DOUBLET-3 DEVICE
ELECTROMAGNETIC RADIATION
ELECTRON TUBES
ELECTRONIC EQUIPMENT
EQUIPMENT
FAR INFRARED RADIATION
INELASTIC SCATTERING
INFRARED RADIATION
LASER RADIATION
LIGHT SCATTERING
MICROWAVE EQUIPMENT
MICROWAVE TUBES
PLASMA DIAGNOSTICS
RADIATIONS
SCATTERING
THERMONUCLEAR DEVICES
THOMSON SCATTERING
TOKAMAK DEVICES