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Proceedings Paper

Polarization-based devices in solar observations at the Sayan Observatory
Author(s): Victor M. Grigoryev; Nikolai I. Kobanov; Valery I. Skomorovsky
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Paper Abstract

Several polarization devices for solar observations designed at Sayan observatory are discussed, namely: (1) An electrooptical deflector is used to analyze circular polarization in a spectral line for longitudinal magnetic field measurements. This deflector located after the spectrograph slit incorporates a KD*P crystal and a Savart-plate. In contrast to usual deflectors, it transmits both Zeeman spectral-line components. But it also produces spatial modulation of separation of the Zeeman-split components. (2) An electrooptical deflector of the same type is located in the focal plane of the spectrograph before the photometer slit, to obtain subsequent measurement of the spectral line wings and the line Doppler shift. (3) An electrooptical analyzer is used to measure the magnetic field vector. It incorporates two KD*P crystals and a polarizing prism. The KD*P crystals are controlled by rectangular voltage pulses (+U(lambda /4), 0, -U(lambda /4) at frequency f0 for the first crystal and +/- U(lambda /4) at 3f0 for the second one). Such an analyzer permits measurement of the Q, U and V Stokes parameters. The properties of the modulator and the control device are discussed. (4) The differential velocity measuring device incorporates an electrooptical deflector and a polarizing beam-splitter located before the spectrograph entrance slit. The device is used to investigate local 5-minute oscillations. The corresponding method of the radial velocity measurements is based on measuring the relative spectral line positions at two different points of the solar image. This method is completely free from spectrograph seeing effects. A modification of this method permits differential solar rotation measurements. The signal calibration methods are also discussed together with their applicability to the determination of the line profile slopness and its variation over the solar image.

Paper Details

Date Published: 14 September 1994
PDF: 11 pages
Proc. SPIE 2265, Polarization Analysis and Measurement II, (14 September 1994); doi: 10.1117/12.186688
Show Author Affiliations
Victor M. Grigoryev, Institute of Solar-Terrestrial Physics (Russia)
Nikolai I. Kobanov, Institute of Solar-Terrestrial Physics (Russia)
Valery I. Skomorovsky, Institute of Solar-Terrestrial Physics (Russia)

Published in SPIE Proceedings Vol. 2265:
Polarization Analysis and Measurement II
Dennis H. Goldstein; David B. Chenault, Editor(s)

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