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Related papers: Machine learning for reconstruction of polarity in…

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Hand-drawn synoptic maps from the Meudon Observatory (1919 onwards) and the McIntosh archive (1967 onwards) are two important sources of long-term, manually recorded filament observations. In this study, we calibrate the Meudon maps and…

Solar and Stellar Astrophysics · Physics 2021-10-13 Rakesh Mazumder , Subhamoy Chatterjee , Dibyendu Nandy , Dipankar Banerjee

The paper presents a reliable method using deep learning to recognize solar filaments in H-alpha full-disk solar images automatically. This method cannot only identify filaments accurately but also minimize the effects of noise points of…

Instrumentation and Methods for Astrophysics · Physics 2019-09-17 GaoFei Zhu , GangHua Lin , DongGuang Wang , Suo Liu , Xiao Yang

In this study, we classify the magnetic chirality of solar filaments from H-Alpha observations using state-of-the-art image classification models. We establish the first reproducible baseline for solar filament chirality classification on…

Solar and Stellar Astrophysics · Physics 2025-09-24 Alexis Chalmers , Azim Ahmadzadeh

We study the extent to which Milne-Eddington inversions are able to retrieve and characterize the magnetic landscape of the solar poles from observations by the spectropolarimeter onboard Hinode. In particular, we evaluate whether a…

Solar and Stellar Astrophysics · Physics 2023-07-05 Rebecca Centeno , Ivan Milić , Matthias Rempel , Nariaki V. Nitta , Xudong Sun

The morphology of circular polarisation profiles from solar spectropolarimetric observations encode information about the magnetic field strength, inclination, and line-of-sight velocity gradients. Previous studies used manual methods or…

Solar and Stellar Astrophysics · Physics 2025-05-21 Ryan James Campbell , Mihalis Mathioudakis , Carlos Quintero Noda , Peter Keys , David Orozco Suárez

In 1964 (Solar Cycle 20; SC 20), Patrick McIntosh began creating hand-drawn synoptic maps of solar magnetic features, based on H$\alpha$ images. These synoptic maps were unique in that they traced magnetic polarity inversion lines, and…

Solar and Stellar Astrophysics · Physics 2018-08-27 Sarah E. Gibson , David Webb , Ian M. Hewins , Robert H. McFadden , Barbara A. Emery , William Denig , Patrick S. McIntosh

Solar filaments show the position of large scale polarity inversion lines and are used for the reconstruction of large-scale solar magnetic field structure on the basis of H{\alpha} synoptic charts for the periods when magnetographic…

Solar and Stellar Astrophysics · Physics 2015-05-27 Boris Filippov , A. K. Srivastava

Filaments and coronal holes, two principal features observed in the solar corona are sources of space weather variations. Filament formation is closely associated with polarity inversion lines (PIL) on the solar photosphere which separate…

Solar and Stellar Astrophysics · Physics 2018-11-28 Rakesh Mazumder , Prantika Bhowmik , Dibyendu Nandy

Accurate modeling of the Sun's coronal magnetic field and solar wind structures require inputs of the solar global magnetic field, including both the near and far sides, but the Sun's far-side magnetic field cannot be directly observed.…

Solar and Stellar Astrophysics · Physics 2023-01-04 Ruizhu Chen , Junwei Zhao , Shea Hess Webber , Yang Liu , J. Todd Hoeksema , Marc L. Derosa

Inferring the three-dimensional (3D) solar atmospheric structures from observations is a critical task for advancing our understanding of the magnetic fields and electric currents that drive solar activity. In this work, we introduce a…

Polar fields at the minimum of a sunspot cycle -- which are a manifestation of the radial component of the Sun's poloidal field -- are deemed to be the best indicator of the strength of the toroidal component, and hence the amplitude of the…

Solar and Stellar Astrophysics · Physics 2025-10-15 Srinjana Routh , Shaonwita Pal , Dibyendu Nandy , Subhamoy Chatterjee , Dipankar Banerjee , Mohd. Saleem Khan

Current post-processing techniques for the correction of atmospheric seeing in solar observations -- such as Speckle interferometry and Phase Diversity methods -- have limitations when it comes to their reconstructive capabilities of solar…

Solar and Stellar Astrophysics · Physics 2020-12-09 John A. Armstrong , Lyndsay Fletcher

The translation of imaging Mueller polarimetry to clinical practice is often hindered by large footprint and relatively slow acquisition speed of the existing instruments. Using polarization-sensitive camera as a detector may reduce…

Recently, there has been growing interest in the use of machine-learning methods for predicting solar flares. Initial efforts along these lines employed comparatively simple models, correlating features extracted from observations of…

Solar and Stellar Astrophysics · Physics 2023-06-21 Varad Deshmukh , Srinivas Baskar , Elizabeth Bradley , Thomas Berger , James D. Meiss

Solar flare forecasting can be realized by means of the analysis of magnetic data through artificial intelligence techniques. The aim is to predict whether a magnetic active region (AR) will originate solar flares above a certain class…

Solar and Stellar Astrophysics · Physics 2022-06-29 Sabrina Guastavino , Francesco Marchetti , Federico Benvenuto , Cristina Campi , Michele Piana

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

We have carried out a statistical study of the average orientation of the magnetic field in solar filaments with respect to their axes for more than 400 samples, based on data taken with daily full-Sun, full-Stokes spectropolarimetric…

Solar and Stellar Astrophysics · Physics 2020-07-29 Yoichiro Hanaoka , Takashi Sakurai

An important issue in the tomographic reconstruction of the solar poles is the relatively rapid evolution of the polar plumes. We demonstrate that it is possible to take into account this temporal evolution in the reconstruction. The…

Astrophysics · Physics 2009-11-13 Nicolas Barbey , Frédéric Auchère , Thomas Rodet , Jean-Claude Vial

Most astrophysical systems, e.g. stellar winds, the diffuse interstellar medium, molecular clouds, are magnetized with magnetic fields that influence almost all of their properties. One of the most informative techniques of magnetic field…

Astrophysics · Physics 2009-11-07 A. Lazarian

Optical approaches for wavefront shaping traditionally rely on phase modulation through holographic techniques. Shaping the phase determines a wave's diffraction and hence its intensity distribution in space. We instead show that shaping…

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