<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>Nowadays there is increasing interest in narrowing coronal areas with reduced brightness temperatures (LTR – Low Temperature Regions) associated with local open magnetic fields (S-web, “coronal partings”, “dark coronal corridors”) as one of the eventual sources of slow solar wind. Ventspils International Radio Astronomy Centre (VIRAC) performs routine spectral polarimetric observations of the Sun with RT-32 radio telescope equipped with the multi-channel (16 frequency channels) spectral polarimeter for the wave length range of 3.2–4.7 cm (6.3–9.3 GHz) and both circular polarizations simultaneously. The analysis of relevant tasks of clear and reliable observations and detections of LTR shows the necessity to improve noise parameters, dynamic range and stability of the actual solar spectral polarimeter and to expand its wavelength range. Taking into account these requirements, the low noise and thermally stabilized solar spectral polarimeter was developed. The new multi-channel spectral polarimeter is expected to observe right and left circular polarization of the solar emission in the wavelength range of 2.1–7.5 cm (4.1–14.3 GHz) divided into 12 frequency bands. The dynamic range was expanded to >36 db and the signal/noise ratio (referred to as quiet Sun brightness temperatures) was enhanced to > 22–24 db.</p>
<p>The paper deals with some test observations of the newly developed solar spectral polar-imeter and its feature analysis. Some eventual problems of solar physics which could be solved with the spectral polarimeter are also discussed.</p>
</abstract>

Nowadays there is increasing interest in narrowing coronal areas with reduced brightness temperatures (LTR – Low Temperature Regions) associated with local open magnetic fields (S-web, “coronal partings”, “dark coronal corridors”) as one of the eventual sources of slow solar wind. Ventspils International Radio Astronomy Centre (VIRAC) performs routine spectral polarimetric observations of the Sun with RT-32 radio telescope equipped with the multi-channel (16 frequency channels) spectral polarimeter for the wave length range of 3.2–4.7 cm (6.3–9.3 GHz) and both circular polarizations simultaneously. The analysis of relevant tasks of clear and reliable observations and detections of LTR shows the necessity to improve noise parameters, dynamic range and stability of the actual solar spectral polarimeter and to expand its wavelength range. Taking into account these requirements, the low noise and thermally stabilized solar spectral polarimeter was developed. The new multi-channel spectral polarimeter is expected to observe right and left circular polarization of the solar emission in the wavelength range of 2.1–7.5 cm (4.1–14.3 GHz) divided into 12 frequency bands. The dynamic range was expanded to >36 db and the signal/noise ratio (referred to as quiet Sun brightness temperatures) was enhanced to > 22–24 db.
The paper deals with some test observations of the newly developed solar spectral polar-imeter and its feature analysis. Some eventual problems of solar physics which could be solved with the spectral polarimeter are also discussed.

Microwave Observations of the Sun with Virac RT-32 Radio Telescope: The Expansion of Possibilities

Latvian Journal of Physics and Technical Sciences

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Nowadays there is increasing interest in narrowing coronal areas with reduced brightness temperatures (LTR – Low Temperature Regions) associated with local...

Microwave Observations of the Sun with Virac RT-32 Radio Telescope: The Expansion of Possibilities

Published Online: Jun 23, 2022

Page range: 5 - 13

DOI: https://doi.org/10.2478/lpts-2022-0019

Keywords
Radio astronomy, slow solar wind, solar physics, spectral polarimeter

© 2022 D. Bezrukovs, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Microwave Observations of the Sun with Virac RT-32 Radio Telescope: The Expansion of Possibilities

Published Online: Jun 23, 2022

Page range: 5 - 13

DOI: https://doi.org/10.2478/lpts-2022-0019

KeywordsRadio astronomy, slow solar wind, solar physics, spectral polarimeter

© 2022 D. Bezrukovs, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
Radio astronomy, slow solar wind, solar physics, spectral polarimeter