Heterodyne Interferometer/Polarimeter for Sensing Alfvén Activity in the H-1 Heliac
نویسنده
چکیده
A phase-sensitive heterodyne interferometer/polarimeter for measurement of electron densities and plasma fluctuation structures is described. The instrument utilizes a frequency swept-source to provide a frequency offset for heterodyne detection methods. Only two detectors are required to obtain the interferometric and polarimetric information which is encoded as a phase modulation on the intermediate frequency carrier signals. Fluctuations in the H-1 plasma showing Alfvénic scaling 1/ √ ne are observed. Pure m = 3 and m = 4 angular harmonic mode structures are observed to exist for different magnetic field configurations. A phase shift between the polarimeter and interferometer signals arising due to the magnetic field component along the line of sight is also observed.
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