title: High-frequency fluctuation measurements by far-infrared laser Faraday-effect polarimetry-interferometry and forward scattering system on MST.
abstract: 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(-1) for beam width w = 1.5 cm and 15 cm(-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.
authors.affiliation: Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: W X
authors.initials: WX
authors.lastname: Ding
authors.affiliation: Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: L
authors.initials: L
authors.lastname: Lin
authors.affiliation: Department of Physics, University of Wisconsin-Madison, Wisconsin 53706, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Duff
authors.affiliation: Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Brower