The Bulletin of The Korean Astronomical Society (천문학회보)
- Volume 43 Issue 2
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- Pages.47.1-47.1
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- 2018
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- 1226-2692(pISSN)
Distribution characteristics of a solar-surface magnetic field in the recent four solar cycles
- Magara, Tetsuya (Department of Astronomy and Space Science, Kyung Hee University) ;
- An, Junmo (School of Space Research, Kyung Hee University) ;
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Lee, Hwanhee
(School of Space Research, Kyung Hee University)
- Published : 2018.10.10
Abstract
Solar cycles are inherent to the Sun, which experiences temporal changes in its magnetic activity via the surface distribution of the solar magnetic field. This raises a fundamental question of how to derive the distribution characteristics of a solar-surface magnetic field that are responsible for individual solar cycles. We present a new approach to deriving as long-term and large-scale distribution characteristics of this quantity as was ever obtained; that is, we conducted a population ecological analysis of Wilcox Solar Observatory (WSO) Synoptic Charts which provide a more than 40-year time series of latitude-longitude maps of solar-surface magnetic fields. In this approach, solar-surface magnetic fields are assumed as hypothetical trees with magnetic polarities (magnetic trees) distributed on the Sun. Accordingly, we identified a peculiarity of cycle 23 with a longer period than an average period of 11 years; specifically we found that the negative surface magnetic field had much more clumped distributions than the positive surface magnetic field during the first one-third of this cycle, while the latter was dominant over the former. The Sun eventually spent more than one-third of cycle 23 recovering from these imbalances.
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