Low Brightness Temperature in Microwaves at Periphery of Some Solar Active Regions

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2017-06-27
Major/Subject
Mcode
Degree programme
Language
en
Pages
10
58-67
Series
Latvian Journal of Physics and Technical Sciences, Volume 54, issue 3
Abstract
The microwave regions with low brightness temperature are found to overlap the regions of the depressed coronal emission and open field lines at the periphery of two solar active regions (ARs). The imaging microwave observations of the Sun with the Nobeyama Radio heliograph at 1.76 cm, the MRO-14 radio telescope of Metsähovi Radio Observatory at 0.8 cm, and the RT-32 of Ventspils International Radio Astronomy Centre in the range 3.2-4.7 cm are used. To reduce the noise in the intensity distribution of the RT-32 maps of the Sun, one wavelet plane of "à trous" wavelet space decomposition is subtracted from each map. To locate the open-field regions, the full-Sun coronal magnetic fields with the potential field source surface (PFSS) model for RSS = 1.8 R are simulated. We conclude that the revealed LTRs present narrow coronal hole-like regions near two ARs and imply an extra investigation on the plasma outflow.
Description
Keywords
microwave radiation, solar active region, solar atmosphere
Other note
Citation
Ryabov , B I , Bezrukov , D A & Kallunki , J 2017 , ' Low Brightness Temperature in Microwaves at Periphery of Some Solar Active Regions ' , Latvian Journal of Physics and Technical Sciences , vol. 54 , no. 3 , pp. 58-67 . https://doi.org/10.1515/lpts-2017-0021 , https://doi.org/10.1515/lpts-2017-0021