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Related papers: Magnetic evolution of complex solar active regions

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We discuss the evolution of solar coronal element abundances over an active region lifetime. Magneto-convection drives the complexity of magnetic fields that emerge above the photosphere. This complexity is dissipated, together with that of…

Solar and Stellar Astrophysics · Physics 2025-12-16 David H. Brooks , Deborah Baker , David M. Long. Paola Testa , Harry P. Warren

Solar flares and coronal mass ejections are among the most prominent manifestations of the magnetic activity of the Sun. The strongest events of them tend to occur in active regions (ARs) that are large, complex, and dynamically evolving.…

Solar and Stellar Astrophysics · Physics 2022-08-17 Shin Toriumi

Solar activity can be witnessed in the form of sunspots and active regions, where the magnetic field is enhanced by up to a factor 1000 as compared to that of the quiet Sun. In addition, solar activity manifests itself in terms of flares,…

Solar and Stellar Astrophysics · Physics 2025-07-25 Gottfried Mann , Frédéric Schuller

Planets orbiting young, solar-type stars are embedded in a more energetic environment than that of the solar neighbourhood. They experience harsher conditions due to enhanced stellar magnetic activity and wind shaping the secular evolution…

Solar and Stellar Astrophysics · Physics 2025-07-22 S. Bellotti , T. Lueftinger , S. Boro Saikia , C. P. Folsom , P. Petit , J. Morin , M. Gudel , J. -F. Donati , E. Alecian

Line-of-sight magnetograms for 217 active regions (ARs) of different flare rate observed at the solar disk center from January 1997 until December 2006 are utilized to study the turbulence regime and its relationship to the flare…

Solar and Stellar Astrophysics · Physics 2015-05-19 Valentyna Abramenko , Vasyl Yurchyshyn

We report a systematic strengthening of the local solar surface or fundamental $f$-mode $1$-$2$ days prior to the emergence of an active region (AR) in the same (corotating) location. Except for a possibly related increase in the kurtosis…

Solar and Stellar Astrophysics · Physics 2016-11-23 Nishant K. Singh , Harsha Raichur , Axel Brandenburg

Among several heliophysical and geophysical quantities, the accurate evolution of the solar irradiance is fundamental to forecast the evolution of the neutral and ionized components of the Earth's atmosphere.We developed an artificial…

Solar and Stellar Astrophysics · Physics 2011-11-23 Luis Eduardo A. Vieira , Thierry Dudok de Wit , Matthieu Kretzschmar

This review provides an introduction to the generation and evolution of the Sun's magnetic field, summarising both observational evidence and theoretical models. The eleven year solar cycle, which is well known from a variety of observed…

Solar and Stellar Astrophysics · Physics 2011-10-17 Alan W. Hood , David W. Hughes

This paper reviews the studies of solar photospheric magnetic field evolution in active regions and its relationship to solar flares. It is divided into two topics, the magnetic structure and evolution leading to solar eruptions and the…

Solar and Stellar Astrophysics · Physics 2015-06-23 Haimin Wang , Chang Liu

Using the non-linear mean-field dynamo models we calculate the magnetic cycle parameters, like the dynamo cycle period, the amplitude of the total magnetic energy, and the Poynting flux luminosity from the surface for the solar analogs with…

Solar and Stellar Astrophysics · Physics 2021-01-27 V. V. Pipin

Here, we developed a complex network of solar active regions (ARs) to study various local and global properties of the network. The values of the Hurst exponent ($0.8-0.9$) were evaluated by both the detrended fluctuation analysis and the…

Solar and Stellar Astrophysics · Physics 2017-08-23 Farhad Daei , Hossein Safari , Neda Dadashi

We analyzed temporal and periodic behavior of sunspot counts (SSCs) in flaring (C, M, or X class flares), and non-flaring active regions (ARs) for the almost two solar cycles (1996 through 2016). Our main findings are as follows: i) The…

Solar and Stellar Astrophysics · Physics 2018-04-25 A. Kilcik , V. Yurchyshyn , B. Donmez , V. N. Obridko , A. Ozguc , J. P. Rozelot

Sequences of line-of-sight (LOS) magnetograms recorded by the Michelson-Doppler Imager are used to quantitatively characterize photospheric magnetic structure and evolution in three active regions that rotated across the Sun's disk during…

Solar and Stellar Astrophysics · Physics 2015-05-27 B. T. Welsch , S. Christe , J. M. McTiernan

The emergence of the magnetic field through the photosphere has multiple manifestations and sunspots are the most prominent examples of this. One of the most relevant sunspot properties, to study both its structure and evolution, is the…

Solar and Stellar Astrophysics · Physics 2012-11-30 R. Gafeira , C. C. Fonte , M. A. Pais , J. Fernandes

The work is devoted to the study of periodic structures in the magnetic field of the photosphere. The polarity of the Sun's magnetic fields shows cyclicity with periods of 1-3 years, which is possibly due to quasi-biennial variations that…

Solar and Stellar Astrophysics · Physics 2025-07-08 Elena Vernova , Marta Tyasto , Dmitrii Baranov

Active regions (ARs) are typical magnetic structures found in the solar atmosphere. We calculate several magnetohydrostatic (MHS) equilibrium models that include the effect of a finite plasma-$\beta$ and gravity and that are representative…

Solar and Stellar Astrophysics · Physics 2023-03-08 Jaume Terradas , Thomas Neukirch

Aims. We investigate the role of the accumulation of both magnetic helicity and magnetic energy in the generation of coronal mass ejections (CMEs) from emerging solar active regions (ARs). Methods. Using vector magnetic field data obtained…

Solar and Stellar Astrophysics · Physics 2022-06-01 E. Liokati , A. Nindos , Y. Liu

We present a detailed investigation on the evolution of observed net vertical current using a time series of vector magnetograms of the active region (AR) NOAA 11158 obtained from Helioseismic Magnetic Imager. We also discuss the relation…

Solar and Stellar Astrophysics · Physics 2015-09-16 P. Vemareddy , P. Venkatakrishnan , S. Karthikreddy

We present new models for the rotational evolution of solar-like stars between 1 Myr and 10 Gyr with the aim to reproduce the distributions of rotational periods observed for star forming regions and young open clusters within this age…

Solar and Stellar Astrophysics · Physics 2015-06-16 Florian Gallet , Jérôme Bouvier

On the base of the solar magnetic field measurements obtained in Stanford in 1976--2003 the properties of the cyclic evolution of the large-scale magnetic field are investigated. Some regularities are found in longitudinal and latitudinal…

Astrophysics · Physics 2007-05-23 R. N. Ikhsanov , V. G. Ivanov
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