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The magnetic fields in the solar polar region are important to our understanding of the internal dynamo process, the global coronal structure, and the origin of the solar wind. The inference of polar fields based on spectropolarimetric…

Solar and Stellar Astrophysics · Physics 2026-03-16 Bryan Yamashiro , Xudong Sun , Ivan Milić , Carlos Quintero Noda , Adur Pastor Yabar , Rebecca Centeno , Jiayi Liu , Milan Gošić , Kai Yang

Context: Faraday rotation measurements of extragalactic radio sources during coronal occultation allow assessment of both the electron density distribution and the three-dimensional magnetic field topology in the outer solar corona. Aims:…

Astrophysics · Physics 2008-11-26 S. Mancuso , M. V. Garzelli

We present the result of comparison between magnetic field parameters and the intensity of X-ray emission for solar microflares with Geosynchronous Operational Environmental Satellites (GOES) classes from A0.02 to B5.1. For our study, we…

Solar and Stellar Astrophysics · Physics 2017-08-30 A. S. Kirichenko , S. A. Bogachev

The magnetic field inside the sunspot umbra, as observed by the Full-disk MagnetoGraph (FMG) onboard the Advanced Space based Solar Observatory (ASO-S), was found to be experiencing a weakening. To address this issue, we employed a method…

Solar and Stellar Astrophysics · Physics 2024-05-30 Haiqing Xu , Jiangtao Su , Suo Liu , Yuanyong Deng , Xianyong Bai , Jie Chen , Xiaofan Wang , Xiao Yang , Yongliang Song

Extrapolations of solar photospheric vector magnetograms into three-dimensional magnetic fields in the chromosphere and corona are usually done under the assumption that the fields are force-free. The field calculations can be improved by…

Solar and Stellar Astrophysics · Physics 2015-05-20 M. Fuhrmann , N. Seehafer , G. Valori , T. Wiegelmann

The adopted WSA model embedded in EUHFORIA (EUropean Heliospheric FORecasting Information Asset) is compared to EUV observations. According to the standard paradigm coronal holes are sources of open flux thus we use remote sensing EUV…

Solar and Stellar Astrophysics · Physics 2020-01-08 Eleanna Asvestari , Stephan G. Heinemann , Mannuela Temmer , Jens Pomoell , Emilia Kilpua , Jasmina Magdalenic , Stefaan Poedts

Aims. We report the small temporal variation of the axial dipole moment near the solar minimum and its application to the solar cycle prediction by the surface flux transport (SFT) model. Methods. We measure the axial dipole moment using…

Solar and Stellar Astrophysics · Physics 2017-11-08 H. Iijima , H. Hotta , S. Imada , K. Kusano , D. Shiota

We study the evolution of the observed photospheric magnetic field and the modeled global coronal magnetic field during the past 3 1/2 solar activity cycles observed since the mid-1970s. We use synoptic magnetograms and extrapolated…

Solar and Stellar Astrophysics · Physics 2015-06-15 G. J. D. Petrie

We address the problem of calculating the transverse magnetic field in the solar wind outside of the hypothetical sphere called the source surface where the solar wind originates. This calculation must overcome a widely used fundamental…

Solar and Stellar Astrophysics · Physics 2016-04-27 Roger K. Ulrich , Tham Tran

The surface flux transport (SFT) model of solar magnetic fields involves empirically well-constrained velocity and magnetic fields. The basic evolution of the Sun's large-scale surface magnetic field is well described by this model. The…

Solar and Stellar Astrophysics · Physics 2015-06-05 R. H. Cameron , D. Schmitt , J. Jiang , E. Isik

The results of 2D MHD simulations of solar magnetogranulation are used to analyze the horizontal magnetic fields and the response of the synthesized Stokes profiles of the FeI 1564.85 nm line to the magnetic fields. Selected 1.5-h series of…

Solar and Stellar Astrophysics · Physics 2009-06-16 V. A. Sheminova

Small scale magnetic fields can be observed on the Sun in G-band filtergrams as MBPs (magnetic bright points) or identified in spectro-polarimetric measurements due to enhanced signals of Stokes profiles. These magnetic fields and their…

Solar and Stellar Astrophysics · Physics 2015-06-15 D. Utz , J. Jurčák , A. Hanslmeier , R. Muller , A. Veronig , O. Kühner

We report on new spectro-polarimetric measurements with simultaneous filter imaging observation, revealing the frequent appearance of polarization signals indicating high-speed, probably supersonic, downflows that are associated with at…

It is widely believed that loops observed in the solar atmosphere trace out magnetic field lines. However, the degree to which magnetic field extrapolations yield field lines that actually do follow loops has yet to be studied…

Solar and Stellar Astrophysics · Physics 2018-06-27 Harry P. Warren , Nicholas A. Crump , Ignacio Ugarte-Urra , Xudong Sun , Markus J. Aschwanden , Thomas Wiegelmann

We review the surface flux transport model for the evolution of magnetic flux patterns on the Sun's surface. Our underlying motivation is to understand the model's prediction of the polar field (or axial dipole) strength at the end of the…

Solar and Stellar Astrophysics · Physics 2023-05-31 Anthony R. Yeates , Mark C. M. Cheung , Jie Jiang , Kristof Petrovay , Yi-Ming Wang

By use of the high-resolution spectral data and the broadband imaging obtained with the Goode Solar Telescope at the Big Bear Solar Observatory on 2013 June 6, the spectra of three typical photospheric bright points (PBPs) have been…

Solar and Stellar Astrophysics · Physics 2020-07-21 Q. Hao , C. Fang , M. D. Ding , Z. Li , W. Cao

Before using 3D MHD simulations of the solar photosphere in the determination of elemental abundances, one has to ensure that the correct amount of magnetic flux is present in the simulations. The presence of magnetic flux modifies the…

Solar and Stellar Astrophysics · Physics 2017-06-28 C. Beck , D. Fabbian , R. Rezaei , K. G. Puschmann

Polarisation measurements of solar flares at millimetre-waves were used to investigate the magnetic field configuration of the emitting sources. We analyse two solar flares (SOL2013-02-17 and SOL2013-11-05) observed by the POlarisation…

Solar and Stellar Astrophysics · Physics 2020-05-05 Douglas F. da Silva , Paulo J. A. Simões , R. F. Hidalgo Ramírez , Adriana Válio

(Abridged) This paper introduces the formalism which connects between rotation measure ($\RM$) measurements for extragalactic sources and the cosmological magnetic field power spectrum. It is shown that the amplitude and shape of the…

Astrophysics · Physics 2016-08-30 Tsafrir Kolatt

We present a new model of total solar irradiance (TSI) based on magnetograms simulated with a surface flux transport model (SFTM) and the SATIRE (Spectral And Total Irradiance REconstructions) model. Our model provides daily maps of the…

Solar and Stellar Astrophysics · Physics 2014-10-15 M. Dasi-Espuig , J. Jiang , N. A. Krivova , S. K. Solanki
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