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Related papers: Properties of Magnetic Tongues over a Solar Cycle

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Elongated magnetic polarities are observed during the emergence phase of bipolar active regions (ARs). These extended features, called magnetic tongues, are interpreted as a consequence of the azimuthal component of the magnetic flux in the…

Solar and Stellar Astrophysics · Physics 2015-05-08 Mariano Poisson , Cristina H. Mandrini , Pascal Démoulin , Marcelo López Fuentes

The magnetic polarities of bipolar active regions (ARs) exhibit elongations in line-of-sight magnetograms during their emergence. These elongations are referred to as magnetic tongues and attributed to the presence of twist in the emerging…

Solar and Stellar Astrophysics · Physics 2020-01-29 M. Poisson , M. C. López Fuentes , C. H. Mandrini , P. Démoulin , C. MacCormack

Active regions (ARs) appear in the solar atmosphere as a consequence of the emergence of magnetic flux ropes (FRs). Due to the presence of twist, the photospheric line-of-sight (LOS) magnetograms of emerging ARs show an elongation of the…

Solar and Stellar Astrophysics · Physics 2023-12-12 M. Poisson , M. López Fuentes , C. H. Mandrini , F. Grings , P. Démoulin

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

Context. Active regions (ARs) appear in the solar atmosphere as a consequence of the emergence of magnetic flux tubes. The presence of elongated magnetic polarities in line-of-sight (LOS) magnetograms indicates the existence of twist in the…

Solar and Stellar Astrophysics · Physics 2022-09-14 M. Poisson , F. Grings , C. H. Mandrini , M. López-Fuentes , P. Démoulin

We study the long term evolution of a set of 22 bipolar active regions (ARs) in which the main photospheric polarities are seen to rotate one around the other during several solar rotations. We first show that differential rotation is not…

Solar and Stellar Astrophysics · Physics 2015-06-23 M. López Fuentes , P. Démoulin , C. H. Mandrini , A. A. Pevtsov , L. van Driel-Gesztelyi

The presence of elongations in active region (AR) polarities, called magnetic tongues, are mostly visible during their emergence phase. AR tilts have been measured thoroughly using long-term white-light (WL) databases, sometimes combined…

Solar and Stellar Astrophysics · Physics 2020-05-27 M. Poisson , P. Démoulin , C. H. Mandrini , M. C. López Fuentes

Our aim is to study the photospheric flux distribution of a twisted flux tube that emerges from the solar interior. We also report on the eruption of a new flux rope when the emerging tube rises into a pre-existing magnetic field in the…

Solar and Stellar Astrophysics · Physics 2010-03-12 V. Archontis , A. W. Hood

We perform a study of fluid motions and its temporal evolution in and around a small bipolar emerging flux region using observations made by the Helioseismic and Magnetic Imager (HMI) on-board the Solar Dynamics Observatory (SDO). We employ…

Solar and Stellar Astrophysics · Physics 2020-06-03 C. R. Sangeetha , Durgesh Tripathi , S. P. Rajaguru

We analyse the topology of photospheric magnetic fields and sub-photospheric flows of several active regions (ARs) that are observed during the peak to descending phase of the solar cycle 23. Our analysis shows clear evidence of hemispheric…

Solar and Stellar Astrophysics · Physics 2020-08-12 R. A. Maurya , A. Ambastha

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

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

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…

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

Using time-sequence vector magnetic field and coronal observations from \textit{Solar Dynamics Observatory}, we report the observations of the magnetic field evolution and coronal activity in four emerging active regions (ARs). The ARs…

Solar and Stellar Astrophysics · Physics 2022-08-24 P. Vemareddy

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

We present a series of numerical experiments that model the evolution of magnetic flux tubes with a different amount of initial twist. As a result of calculations, tightly twisted tubes reveal a rapid two-step emergence to the atmosphere…

Solar and Stellar Astrophysics · Physics 2015-05-20 Shin Toriumi , Takehiro Miyagoshi , Takaaki Yokoyama , Hiroaki Isobe , Kazunari Shibata

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 a 3D non-linear mean-field solar dynamo model, we investigate the magnetic helicity flux and magnetic twist, and tilt parameters of bipolar magnetic regions (BMRs) emerging from the solar convection zone due to the magnetic buoyancy…

Solar and Stellar Astrophysics · Physics 2025-08-04 V. V. Pipin , Shangbin Yang , A. G. Kosovichev

Bipolar sunspots, or more generally, Bipolar Magnetic Regions, BMRs, are the dynamic magnetic regions that appear on the solar surface and are central to solar activity. One striking feature of these regions is that they are often tilted…

Solar and Stellar Astrophysics · Physics 2025-12-18 Anu Sreedevi , Bidya Binay Karak , Bibhuti Kumar Jha , Rambahadur Gupta , Dipankar Banerjee
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