High-frequency fluctuation measurements by far-infrared laser Faraday-effect polarimetry-interferometry and forward scattering system on MST
- Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095 (United States)
- Department of Physics, University of Wisconsin-Madison, Wisconsin 53706 (United States)
Magnetic fluctuation-induced transport driven by global tearing modes has been measured by Faraday-effect polarimetry and interferometry (phase measurements) in the MST reversed field pinch. However, the role of small-scale broadband magnetic and density turbulence in transport remains unknown. In order to investigate broadband magnetic turbulence, we plan to upgrade the existing detector system by using planar-diode fundamental waveguide mixers optimized for high sensitivity. Initial tests indicate these mixers have ×10 sensitivity improvement compared to currently employed corner-cube Schottky-diode mixers and ×5 lower noise. Compact mixer design will allow us to resolve the wavenumbers up to k ∼ 1–2 cm{sup −1} for beam width w = 1.5 cm and 15 cm{sup −1} for beam width w = 2 mm. The system can also be used to measure the scattered signal (amplitude measurement) induced by both plasma density and magnetic fluctuations.
- OSTI ID:
- 22303827
- Journal Information:
- Review of Scientific Instruments, Vol. 85, Issue 11; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
AMPLITUDES
BEAM PROFILES
FAR INFRARED RADIATION
FARADAY EFFECT
FLUCTUATIONS
INTERFEROMETRY
LASERS
PLASMA DENSITY
POLARIMETRY
REVERSED-FIELD PINCH DEVICES
SCATTERING
SCHOTTKY BARRIER DIODES
SENSITIVITY
TEARING INSTABILITY