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In this article, we present the application of the weighted horizontal gradient of magnetic field (WGM) flare prediction method to 3-dimensional (3D) extrapolated magnetic configurations of 13 flaring solar active regions (ARs). The main…

Solar and Stellar Astrophysics · Physics 2020-06-24 M. B. Korsos , M. K. Georgoulis , N. Gyenge , S. K. Bisoi , S. Yu , S. Poedts , C. J. Nelson , J. Liu , Y. Yan , R. Erdelyi

Simultaneous measurement of line-of-sight (LOS) magnetic and velocity fields at the photosphere and chromosphere are presented. Fe I line at $\lambda6569$ and $H_{\alpha}$ at $\lambda6563$ are used respectively for deriving the physical…

Astrophysics · Physics 2009-11-13 K. Nagaraju , K. Sankarasubramanian , K. E. Rangarajan

Magnetic field extrapolation is a fundamental tool to reconstruct the three-dimensional magnetic field above the solar photosphere. However, the prevalently used force-free field model might not be applicable in the lower atmosphere with…

Solar and Stellar Astrophysics · Physics 2023-07-12 Fu Yu , Jie Zhao , Yang Su , Xiaoshuai Zhu , Yang Guo , Jinhua Shen , Hui Li

Patsourakos et al. (Astrophys. J. 817, 14, 2016) and Patsourakos and Georgoulis (Astron. Astrophys. 595, A121, 2016) introduced a method to infer the axial magnetic field in flux-rope coronal mass ejections (CMEs) in the solar corona and…

Solar and Stellar Astrophysics · Physics 2017-07-19 S. Patsourakos , M. K. Georgoulis

Recent numerical work in helioseismology has shown that a periodically varying subsurface magnetic field leads to a fanning of the $f$-mode, which emerges from the density jump at the surface. In an attempt to model a more realistic…

Solar and Stellar Astrophysics · Physics 2019-12-16 Nishant K. Singh , Harsha Raichur , Maarit J. Käpylä , Matthias Rheinhardt , Axel Brandenburg , Petri J. Käpylä

The solar chromosphere is heated to temperatures higher than predicted by radiative equilibrium. This excess heating is greater in active regions where the magnetic field is stronger. We aim to investigate the magnetic topology associated…

Solar and Stellar Astrophysics · Physics 2022-05-04 J. M. da Silva Santos , S. Danilovic , J. Leenaarts , J. de la Cruz Rodríguez , X. Zhu , S. M. White , G. J. M. Vissers , M. Rempel

We studied the physical parameters of the penumbra in a large and fully-developed sunspot, one of the largest over the last two solar cycles, by using full-Stokes measurements taken at the photospheric Fe I 617.3 nm and chromospheric Ca II…

Solar and Stellar Astrophysics · Physics 2019-03-20 Mariarita Murabito , I. Ermolli , F. Giorgi , M. Stangalini , S. L. Guglielmino , S. Jafarzadeh , H. Socas-Navarro , P. Romano , F. Zuccarello

We present a series of radiative MHD simulations addressing the origin and distribution of mixed polarity magnetic field in the solar photosphere. To this end we consider numerical simulations that cover the uppermost 2-6 Mm of the solar…

Solar and Stellar Astrophysics · Physics 2015-06-19 M. Rempel

Acoustic and magnetoacoustic waves are among the possible candidate mechanisms that heat the upper layers of solar atmosphere. A weak chromospheric plage near a large solar pore NOAA 11005 was observed on October 15, 2008 in the lines Fe I…

Solar and Stellar Astrophysics · Physics 2016-07-27 M. Sobotka , P. Heinzel , M. Švanda , J. Jurčák , D. del Moro , F. Berrilli

We study the properties of slow magneto-acoustic waves that are naturally excited due to turbulent convection and investigate their role in the energy balance of a plage region using three dimensional (3D) radiation-MHD simulations. We…

Solar and Stellar Astrophysics · Physics 2021-08-11 Nitin Yadav , Robert H. Cameron , Sami K. Solanki

We gave an extensive study for the quasi-periodic perturbations on the time profiles of the line of sight (LOS) magnetic field in 10x10 sub-areas in a solar plage region (corresponds to a facula on the photosphere). The perturbations are…

Solar and Stellar Astrophysics · Physics 2022-04-20 Haisheng Ji , Parida Hashim , Zhenxiang Hong , Zhe Xu , Jinhua Shen , Kaifan Ji , Wenda Cao

Recent advances in observational performance and numerical simulations have revolutionised our understanding of the solar chromosphere. This concerns in particular the structure and dynamics on small spatial and temporal scales. As a…

Solar and Stellar Astrophysics · Physics 2009-12-01 Sven Wedemeyer-Böhm

The Sun is replete with magnetic fields, with sunspots, pores and plage regions being their most prominent representatives on the solar surface. But even far away from these active regions, magnetic fields are ubiquitous. To a large extent,…

Solar and Stellar Astrophysics · Physics 2015-11-05 Andreas Lagg , Bruce Lites , Jack Harvey , Sanjay Gosain , Rebecca Centeno

Microflares are small activities in solar low atmosphere, some are in the low corona, and others in the chromosphere. Observations show that some of the microflares are triggered by magnetic reconnection between emerging flux and a…

Solar and Stellar Astrophysics · Physics 2015-06-04 R. -L. Jiang , C. Fang , P. -F. Chen

We use the Cosmic Microwave Background (CMB) anisotropy data from Planck to constrain the spatial fluctuations of the fine-structure constant \alpha. Through Thompson scattering of CMB photons, spatial anisotropies of \alpha lead to…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-07 Jon O'Bryan , Joseph Smidt , Francesco De Bernardis , Asantha Cooray

Three-dimensional (3D) magnetic field in the solar atmosphere provides crucial information to understand the explosive phenomenon such as solar flares and coronal mass ejections. Since it is still hard that we determine the 3D magnetic…

Solar and Stellar Astrophysics · Physics 2026-01-07 Daiki Yamasaki , Takahiro Miyoshi , Satoshi Inoue

We used the Pixelised Wavelet Filtering (PWF) method to compute narrow-band power maps of SDO/AIA imaging datasets in the 1700 \AA{}, 1600 \AA{} and 304 \AA{} bandpasses that correspond to different heights. The cut-off frequency was…

Solar and Stellar Astrophysics · Physics 2014-04-15 Ding Yuan , R. Sych , V. E. Reznikova , V. M. Nakariakov

The physics of the solar chromosphere is complex from both theoretical and modeling perspectives. The plasma temperature from the photosphere to corona increases from ~5,000 K to ~1 million K over a distance of only ~10,000 km from the…

Solar and Stellar Astrophysics · Physics 2020-07-27 Mehmet Sarp Yalim , Avijeet Prasad , Nikolai Pogorelov , Gary Zank , Qiang Hu

To understand the physics of sunspots, it is important to know the properties of their magnetic field, and especially its height stratification plays a substantial role. There are mainly two methods to assess this stratification, but they…

Solar and Stellar Astrophysics · Physics 2018-08-29 Horst Balthasar

Large-aperture coprime arrays (CAs) are expected to achieve higher sensing resolution than conventional dense arrays (DAs), yet with lower hardware and energy cost. However, existing CA far-field localization methods cannot be directly…

Signal Processing · Electrical Eng. & Systems 2024-11-05 Hongqiang Cheng , Changsheng You , Cong Zhou