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We demonstrate that the radial magnetic-field component at the outer boundary of the sunspot penumbra is about 550 Mx cm$^{-2}$ independent of the sunspot area and the maximum magnetic field in the umbra. The mean magnetic-field intensity…

Solar and Stellar Astrophysics · Physics 2022-10-26 V. N. Obridko , M. M. Katsova , D. D. Sokoloff , B. D. Shelting , I. M. Livshits

The LOFAR Two-metre Sky Survey (LoTSS) will map the complete Northern sky and provide an excellent opportunity to study the distribution and evolution of the large-scale structure of the Universe. We study the completeness of the LoTSS…

We apply a novel pre-flare tracking of sunspot groups towards improving the estimation of flare onset time by focusing on the evolution of the 3D magnetic field construction of AR 11429. The 3D magnetic structure is based on potential field…

Solar and Stellar Astrophysics · Physics 2018-08-22 M. B. Korsos , S. Poedts , N. Gyenge , M. K. Georgoulis , S. Yu , S. K. Bisoi , Y. Yan , M. S. Ruderman , R. Erdelyi

The concept of surface-flux transport (SFT) is commonly used in evolving models of the large-scale solar surface magnetic field. These photospheric models are used to determine the large-scale structure of the overlying coronal magnetic…

Solar and Stellar Astrophysics · Physics 2023-04-12 Graham Barnes , Marc L. DeRosa , Shaela I. Jones , Charles N. Arge , Carl J. Henney , Mark C. M. Cheung

We argue that a variety of solar data suggest that the activity-cycle timescale variability of the total irradiance, is produced by structural adjustments of the solar interior. Assuming these adjustments are induced by variations of…

Astrophysics · Physics 2009-10-31 L. H. Li , S. Sofia

Magnetic flux is continuously being removed and replenished on the solar surface. To understand the removal process we carried out 3D radiative MHD simulations of the evolution of patches of photospheric magnetic field with equal amounts of…

Solar and Stellar Astrophysics · Physics 2015-05-30 Robert Cameron , Alexander Voegler , Manfred Schuessler

Metasurfaces (MSs) have recently become an efficient solution for controlling a spatial field distribution according to the demand of an electromagnetic device. In particular, anomalous reflectors based on impenetrable MSs can be realized…

Applied Physics · Physics 2025-05-15 Vyacheslav Ivliev , Stanislav Glybovski

We investigate the geometry of the magnetic field of rotation-powered pulsars. A new method for calculating an angle ($\beta$) between the spin and magnetic dipole axes of a neutron star (NS) in the ejector stage is considered within the…

High Energy Astrophysical Phenomena · Physics 2023-08-16 Vitaliy Kim , Adel Umirbayeva , Yerlan Aimuratov

The R-value is a measure of the strength of photospheric magnetic Polarity Inversion Lines (PILs) in Active Regions (ARs). This work investigates the possibility of a relation between R-value variations and the occurrence of X-class flares…

The hard X-ray flux ratio R of the footpoint sources to the loop-top source has been used to investigate non-thermal electron trapping and precipitation in solar flares. Considering the mission-long Yohkoh Hard X-ray Telescope database,…

Astrophysics · Physics 2009-11-11 M. Tomczak , T. Ciborski

The physical parameters of the sunspot are not fully understood, especially the height dependence of the magnetic field. So far, it is also an open question as to which heights the He I 1083 nm spectral line is formed at. Our aim is to…

Solar and Stellar Astrophysics · Physics 2024-06-12 M. Benko , H. Balthasar , P. Gömöry , C. Kuckein , S. J. González Manrique

We improve the description of the evolution of the Sun's open and total magnetic flux on time scales of years to millenia. In the model employed here the evolution of the solar total and open magnetic flux is computed from the flux emerging…

Solar and Stellar Astrophysics · Physics 2009-11-24 L. E. A. Vieira , S. Solanki

The coronal magnetic field above a particular photospheric region will vanish at a certain number of points, called null points. These points can be found directly in a potential field extrapolation or their density can be estimated from…

Astrophysics · Physics 2009-11-13 D. W. Longcope , C. E. Parnell

Sunspots are regions of decreased brightness on the visible surface of the Sun (photosphere) that are associated with strong magnetic fields. They have been found to be locations associated with solar flares, which occur when energy stored…

Solar and Stellar Astrophysics · Physics 2013-01-24 Sophie A. Murray

Accurate acquisition of high-resolution surface meteorological conditions is critical for forecasting and simulating meteorological variables. Directly applying spatial interpolation methods to derive meteorological values at specific…

Atmospheric and Oceanic Physics · Physics 2025-06-19 Siwei Tu , Jingyi Xu , Weidong Yang , Lei Bai , Ben Fei

The distribution of magnetic field strength at different levels in the solar photosphere outside active regions was obtained on the basis of the 2D MHD simulation of magnetogranulation and the synthesis of the V profiles of the Fe I 1564.8…

Solar and Stellar Astrophysics · Physics 2012-09-28 V. A. Sheminova

The accuracy of Milne-Eddington (ME) inversions, used to retrieve the magnetic field vector, depends upon the signal-to-noise ratio (SNR) of the spectro-polarimetric observations. The SNR in real observations varies from pixel to pixel,…

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

This paper describes a new 2D model for the photospheric evolution of the magnetic carpet. It is the first in a series of papers working towards constructing a realistic 3D non-potential model for the interaction of small-scale solar…

Solar and Stellar Astrophysics · Physics 2011-08-05 Karen A. Meyer , Duncan H. Mackay , Adriaan A. van Ballegooijen , Clare E. Parnell

Analysis of high-resolution spectropolarimetric observations of early-type magnetic stars is currently the most advanced method of obtaining detailed information on their surface magnetic field topologies and horizontal spot distributions.…

Solar and Stellar Astrophysics · Physics 2018-01-24 N. Rusomarov , O. Kochukhov , A. Lundin

Recently, we have developed a method useful for mapping large-scale horizontal velocity fields in the solar photosphere. The method was developed, tuned and calibrated using the synthetic data. Now, we applied the method to the series of…

Astrophysics · Physics 2009-11-13 Michal Svanda , Mirek Klvana , Michal Sobotka , Vaclav Bumba