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Takalo, J. Spatial and Temporal Distribution of Solar Green-Line Corona for Solar Cycles 18 – 24. Sol Phys 297, 118 (2022).

Spatial and temporal distribution of solar green-line corona for Solar Cycles 18 – 24

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Author: Takalo, Jouni1
Organizations: 1Space Physics and Astronomy Research Unit, University of Oulu, POB 3000, FIN-90014, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 5.9 MB)
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Language: English
Published: Springer Nature, 2022
Publish Date: 2022-10-20


The homogeneous coronal data set (HCDS) of the green corona (Fe XIV) and the coronal index of solar activity (CI) have been used to study the time–latitudinal distribution in Solar Cycles 18 – 24 and compared with similar distribution of sunspots, the magnetic fields, and the solar 10.7 cm radio flux. The most important results are: i) the distribution of coronal intensities related to the cycle maximum are different for individual cycles, ii) the poleward migration of the HCDS from mid-latitudes in each cycle exists, even in the extremely weak Cycle 24, and the same is valid for the equatorward migration, iii) the overall values of HCDS are slightly stronger for the northern hemisphere than for the southern one, iv) the distribution of the HDCS is in coincidence with the strongest photospheric magnetic fields (B>50 Gauss) and histograms of the sunspot groups, v) the Gnevyshev gap was confirmed with at least 95% confidence in the CI, however with different behavior for odd and even cycles. Principal component analysis (PCA) showed that the first and second components account for 87.7% and 7.3% of the total variation of the CI. Furthermore, the second PCA component of the green corona was quite different for Cycle 21, compared with other cycles.

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Series: Solar physics
ISSN: 0038-0938
ISSN-E: 1573-093X
ISSN-L: 0038-0938
Volume: 297
Issue: 9
Article number: 118
DOI: 10.1007/s11207-022-02050-0
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: Open Access funding provided by University of Oulu including Oulu University Hospital.
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