Development of a fast solid-state high-resolution density profile reflectometer system on the DIII-D tokamak
- Electrical Engineering Department, Institute of Plasma and Fusion Research, University of California, Los Angeles, California 90095 (United States)
- Department of Applied Science, University of California, Davis, California 94550 (United States)
A new fast-sweep, broadband frequency-modulated reflectometer on the DIII-D tokamak has produced routine, reliable density profiles with high spatial ({le}1 cm) and temporal resolution ({approximately}100 {mu}s). The system utilizes a solid-state microwave source and an active quadrupler, covering the full Q-band (33{endash}50 GHz) and providing high output power (20{endash}60 mW). The rf source frequency is linearized using an arbitrary function generator and the temperature of the source is actively controlled to reduce rf frequency drifts. The system hardware allows the rf frequency to be swept fullband in 10 {mu}s, but, due to digitization limits, the sweep time used currently is 75{endash}100 {mu}s. The reliability of the reconstructed profiles was improved by a combination of fast frequency sweep, which reduces density fluctuation effects on the measurements, and advanced signal analysis based on digital complex demodulation, which improves phase accuracy. The fast-sweep system has resolved fast-changing edge density profiles during edge localized modes with unprecedented resolution. {copyright} {ital 1997 American Institute of Physics.}
- Research Organization:
- General Atomics, San Diego, CA (United States)
- DOE Contract Number:
- AC03-89ER51114
- OSTI ID:
- 451780
- Report Number(s):
- CONF-960543-; ISSN 0034-6748; TRN: 97:006156
- Journal Information:
- Review of Scientific Instruments, Vol. 68, Issue 1; Conference: 11. annual high-temperature plasma diagnostics conference, Monterey, CA (United States), 12-16 May 1996; Other Information: PBD: Jan 1997
- Country of Publication:
- United States
- Language:
- English
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