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Sunspot proper motions and flares of a super active region NOAA 5395, which was the biggest and the most flare-active region in the 22nd sunspot cycle, were analyzed in details. We measured sunspot proper motions by using the H-alpha - 5.0…

Astrophysics · Physics 2009-10-30 Takako T. Ishii , Hiroki Kurokawa , Tsutomu T. Takeuchi

We studied the developing conditions of sigmoid structure under the influence of magnetic non-potential characteristics of a rotating sunspot in the active region (AR) 12158. Vector magnetic field measurements from Helioseismic Magnetic…

Solar and Stellar Astrophysics · Physics 2016-09-28 P. Vemareddy , X. Cheng , B. Ravindra

The recent ALMA maps together with observations of H$_2$O maser emission seem to suggest the presence of a counter-rotation in the obscuring torus of NGC 1068. We propose to explain this phenomenon as due to the influence of a wind,…

Using a thin flux tube model in a rotating spherical shell of turbulent, solar-like convective flows, we find that the distribution of emerging flux tubes in our simulation is inhomogeneous in longitude, with properties similar to those of…

Solar and Stellar Astrophysics · Physics 2015-06-15 Maria A. Weber , Yuhong Fan , Mark S. Miesch

Quiescent filaments appear as absorption features on the solar disk when observed in chromospheric lines and at continuum wavelengths in the millimeter (mm) range. Active region (AR) filaments are their small-scale, low-altitude analogues,…

Solar and Stellar Astrophysics · Physics 2022-04-29 J. M. da Silva Santos , S. M. White , K. Reardon , G. Cauzzi , S. Gunár , P. Heinzel , J. Leenaarts

We investigate the emergence of Active Region NOAA 10790 by means of time--distance helioseismology. Shallow regions of increased sound speed at the location of increased magnetic activity are observed, with regions becoming deeper at the…

Astrophysics · Physics 2009-11-13 S. Zharkov , M. J. Thompson

Predicting the severity of the solar eruptive phenomena like flares and Coronal Mass Ejections (CMEs) remains a great challenge despite concerted efforts for several decades. The advent of high quality vector magnetograms obtained from…

Solar and Stellar Astrophysics · Physics 2015-05-19 Sanjiv Kumar Tiwari , P. Venkatakrishnan , Sanjay Gosain

The extreme space weather conditions resulting from high energetic events likes solar flares and Coronal Mass Ejections (CMEs) demand for reliable space weather forecasting. The magnetic flux tubes while rising through the convection zone…

Solar and Stellar Astrophysics · Physics 2022-10-19 B Lekshmi , Kiran Jain , Rudolf W. Komm , Dibyendu Nandy

A key aim in space weather research is to be able to use remote-sensing observations of the solar atmosphere to extend the lead time of predicting the geoeffectiveness of a coronal mass ejection (CME). In order to achieve this, the magnetic…

Solar and Stellar Astrophysics · Physics 2017-02-16 Erika Palmerio , Emilia K. J. Kilpua , Alexander W. James , Lucie M. Green , Jens Pomoell , Alexey Isavnin , Gherardo Valori

We have analyzed multi-wavelength observations and magnetic-field data for the solar flare of May 10, 2012 (04:18 UT) and have detected a sign inversion of the signal in the line-of-sight magnetic measurements in the umbra of a small spot.…

Solar and Stellar Astrophysics · Physics 2016-10-19 M. A. Livshits , I. Yu. Grigoryeva , I. I. Myshyakov , G. V. Rudenko

Flapping flight and swimming are increasingly studied both due to their intrinsic scientific richness and their applicability to novel robotic systems. Strip theory is often applied to flapping wings, but such modeling is only rigorously…

Fluid Dynamics · Physics 2020-10-15 A. N. Zurman-Nasution , B. Ganapathisubramani , G. D. Weymouth

The coronal magnetic field is the primary driver of solar dynamic events. Linear and circular polarization signals of certain infrared coronal emission lines contain information about the magnetic field, and to access this information,…

Solar and Stellar Astrophysics · Physics 2015-06-15 L. A. Rachmeler , S. E. Gibson , J. B. Dove , C. R. DeVore , Y. Fan

Models and observations have demonstrated that Twisted Flux Ropes (TFRs) play a significant role in the structure and eruptive dynamics of active regions. Their role in the dynamics of the quiet Sun atmosphere on has remained elusive, their…

Solar active regions (ARs) that produce strong flares and coronal mass ejections (CMEs) are known to have a relatively high non-potentiality and are characterized by delta-sunspots and sheared magnetic structures. In this study, we conduct…

Solar and Stellar Astrophysics · Physics 2017-11-29 Shin Toriumi , Shinsuke Takasao

We numerically study the evolution of magnetic fields and fluid flows in a thin spherical shell. We take the initial field to be a latitudinally confined, predominantly toroidal flux tube. For purely toroidal, untwisted flux tubes, we…

Solar and Stellar Astrophysics · Physics 2009-12-29 R. Hollerbach , P. S. Cally

Basic scenarios and mechanisms for the formation and decay of small-scale magnetic elements and their manifestation in synthesized Stokes profiles of the Fe I 15648.5 A infrared line are considered in the context of two-dimensional modeling…

Solar and Stellar Astrophysics · Physics 2012-10-15 V. A. Sheminova , A. S. Gadun

This study investigates the gravitational waves (GWs) generated by the emergence of magnetic flux tubes in the solar convection zone. We focus on the upward buoyancy of magnetic flux tubes, which leads to significant magnetic activity and…

Solar and Stellar Astrophysics · Physics 2025-10-17 Siqi Guan , Shangbin Yang , Xiao Guo

Low-altitude twisted magnetic fields may be relevant to atmospheric heating in the quiet Sun, but the exact role, topology, and formation of these twisted fields remains to be studied. We investigate the formation and evolution of a…

Solar and Stellar Astrophysics · Physics 2023-05-10 Rebecca Robinson , Guillaume Aulanier , Mats Carlsson

In this study, we explore the elongated granulations and stretched dark lanes within the emerging anti-Hale active region NOAA 12720. Utilizing high-resolution observations from the New Vacuum Solar Telescope, we discern a prevalence of…

Solar and Stellar Astrophysics · Physics 2024-09-17 Jincheng Wang , Xiaoli Yan

We study the emergence of magnetic flux from the near-surface layers of the solar convection zone into the photosphere. To model magnetic flux emergence, we carried out a set of numerical radiative magnetohydrodynamics simulations. Our…

Astrophysics · Physics 2009-11-13 Mark Chun Ming Cheung , Manfred Schuessler , Fernando Moreno-Insertis
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