English
Related papers

Related papers: Magnetic evolution of complex solar active regions

200 papers

Aims. Our aim is to examine the solar cycle variability of magnetically simple and complex active region. Methods. We studied simple ($\alpha$ and $\beta$) and complex ($\beta\gamma$ and $\beta\gamma\delta$) active regions based on the…

Solar and Stellar Astrophysics · Physics 2019-09-11 Shabnam Nikbakhsh , Eija Tanskanen , Maarit Käpylä , Thomas Hackman

Context: Solar active regions (ARs) are key manifestations of the Sun's magnetic activity, displaying diverse spatial and temporal characteristics. Their formation and evolution play a crucial role in understanding the solar dynamo and…

Solar and Stellar Astrophysics · Physics 2025-08-06 M. Švanda , J. Jurčák , M. Schmassmann

The coronal magnetic field evolution of 20 bipolar active regions (ARs) is simulated from their emergence to decay using the time-dependent nonlinear force-free field method of Mackay et al. A time sequence of cleaned photospheric…

Solar and Stellar Astrophysics · Physics 2021-01-13 Stephanie L. Yardley , Duncan H. Mackay , Lucie M. Green

Aims. Although the temporal evolution of active regions (ARs) is relatively well understood, the processes involved continue to be the subject of investigation. We study how the magnetic field of a series of ARs evolves with time to better…

Magnetic active regions on the Sun are harbingers of space weather events. Understanding the physics of how they form and evolve will improve space weather forecasting. Our aim is to characterise the surface magnetic field and flows for a…

Solar and Stellar Astrophysics · Physics 2023-12-08 Camron S. Alley , Hannah Schunker

The study of solar active regions (ARs) is of central importance to a range of fundamental science, as well as the practical applications of space weather. Active region emergence and life cycles are two areas of particular interest, yet…

Solar and Stellar Astrophysics · Physics 2025-10-30 Emily I. Mason , Kara L. Kniezewski

Solar active regions (ARs) are the primary drivers of space weather events, making their early prediction crucial for operational forecasting systems. We develop machine learning models capable of predicting the evolution of magnetic flux…

Solar and Stellar Astrophysics · Physics 2026-04-07 Eren Dogan , Spiridon Kasapis , Sarang Patil , Jonas Tirona , John Stefan , Irina Kitiashvili , Mengjia Xu , Alexander Kosovichev

Using a recently suggested magneto-morphological classification (MMC, Abramenko, 2021, MNRAS Vol 507) of solar active regions (ARs), we explored 3048 ARs, observed from12 May 1996 to 27 December 2021. Magnetograms were acquired with the…

Solar and Stellar Astrophysics · Physics 2026-01-21 Anastasiya Zhukova , Valentina Abramenko

Long-term evolution characteristics of the solar transition region have been unclear. In this study, daily images of the solar full disk derived from the observations by the Solar Dynamics Observatory/Atmospheric Imaging Assembly at 304 A…

Solar and Stellar Astrophysics · Physics 2024-12-13 W. Q. Chen , K. J. Li , J. C. Xu

Magnetic flux emergence and decay in the Sun span from days to months. However, their tracking is typically limited to about half a solar rotation when relying on single-vantage-point observations. Combining observations from both the…

Solar and Stellar Astrophysics · Physics 2026-01-14 I. Kontogiannis , Y. Zhu , K. Barczynski , M. Z. Stiefel , H. Collier , J. McKevitt , J. S. Castellanos Durán , S. Berdyugina , L. K. Harra

Solar active regions (ARs) are crucial for understanding the long-term evolution of solar activities and predicting eruptive phenomena, including solar flares and coronal mass ejections. However, the cycle-dependent properties in the…

Solar and Stellar Astrophysics · Physics 2025-04-25 Yuxia Liu , Tingting Xu , Miao Wan , Linhua Deng , Xinhua Zhao , Shiyang Qi , Nanbin Xiang , Weihong Zhou

Identifying solar active regions (ARs), which consist of one or more pairs of magnetic patches with opposite polarities, is essential due to their significant role in dynamic solar atmospheric phenomena. In this study, we analyze ARs during…

Solar and Stellar Astrophysics · Physics 2025-09-16 Zahra Tajik , Hasan Rezaei , Mehdi Simiari , Hossien Safari

We developed Long Short-Term Memory (LSTM) models to predict the formation of active regions (ARs) on the solar surface. Using the Doppler shift velocity, the continuum intensity, and the magnetic field observations from the Solar Dynamics…

Solar and Stellar Astrophysics · Physics 2024-09-27 Spiridon Kasapis , Irina N. Kitiashvili , Alexander G. Kosovichev , John T. Stefan

Magnetic flux ropes (FRs) are twisted structures appearing on the sun, predominantly in the magnetically concentrated regions. These structures appear as coronal features known as filaments or prominences in H$\alpha$ observations, and as…

Solar and Stellar Astrophysics · Physics 2024-10-04 P. Vemareddy

Active regions (ARs) appear in the solar atmosphere as a consequence of the emergence of magnetic flux-ropes (FR). In this study, we use Bayesian methods to analyze line-of-sight magnetograms of emerging ARs. We employ a FR model consisting…

Solar and Stellar Astrophysics · Physics 2024-05-21 Mariano Poisson , Marcelo López Fuentes , Cristina H. Mandrini , Pascal Démoulin , Francisco Grings

Linking solar wind properties to the activities and characteristics of its source regions can enhance our understanding of its origin and generation mechanisms. Using the Mount Wilson magnetic classification (MWMC), we categorize all active…

Solar and Stellar Astrophysics · Physics 2025-10-13 Xinzheng Shi , Hui Fu , Zhenghua Huang , Limei Yan , Qi Liu , Lidong Xia

In this article, the physical processes occurring in the convective layer and the photosphere of the Sun and their connection to the formation of active regions (ARs) and the development of the corresponding magnetic field are explored.…

Solar and Stellar Astrophysics · Physics 2024-02-22 Aidar M. Sadykov , Sergey A. Krasotkin

Using vector magnetograms from the HMI/SDO and a magnetic connectivity-based method, we calculate the instantaneous relative magnetic helicity and free magnetic energy budgets for several days in two solar active regions (ARs), AR11890 and…

Solar and Stellar Astrophysics · Physics 2023-03-29 E. Liokati , A. Nindos , M. K. Georgoulis

Solar magnetic fields evolve on many time-scales, e.g., the generation, migration, and dissipation of magnetic flux during the 22-year magnetic cycle of the Sun. Active regions develop and decay over periods of weeks. The build-up of…

Astrophysics · Physics 2009-11-13 C. Denker , K. G. Strassmeier

Studying the hemispheric distribution of active regions (ARs) with different magnetic morphology may clarify the features of the dynamo process that is hidden under the photospheric level. The magnetic flux data for 3047 ARs from the CrAO…

Solar and Stellar Astrophysics · Physics 2024-07-10 A. Zhukova
‹ Prev 1 2 3 10 Next ›