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The weak field approximation (WFA) is a conceptually simple and computationally light method for inferring the magnetic field strength and its orientation in the Sun's atmosphere. In this work we study the validity and limitations of this…

Solar and Stellar Astrophysics · Physics 2018-11-09 Rebecca Centeno

We study the effects of finite spectral resolution on the magnetic field values retrieved through the weak field approximation (WFA) from the cores of the Mg II h & k lines. The retrieval of the line-of-sight (LOS) component of the magnetic…

Solar and Stellar Astrophysics · Physics 2022-09-28 Rebecca Centeno , Matthias Rempel , Roberto Casini , Tanausu del Pino Aleman

Aims. We use high-resolution spectropolarimetric observations in the Ca ii 8542 A line obtained with the SST to study the magnetic field in solar spicules. Methods. The equations that result from the application of the Weak Field…

Solar and Stellar Astrophysics · Physics 2020-10-07 M. Kriginsky , R. Oliver , N. Freij , D. Kuridze , A. Asensio Ramos , P. Antolin

We aim to test the reliability of determining the line-of-sight magnetic field from a 3D MHD simulation of a unipolar region. In contrast to earlier similar studies, we consider the full solar disk, i.e. considering the full centre-to-limb…

Solar and Stellar Astrophysics · Physics 2024-10-23 Jonas Sinjan , Sami K. Solanki , Johann Hirzberger , Tino L. Riethmüller , Damien Przybylski

We investigated the diagnostic potential of the Stokes $V$ profile of the H$\alpha$ line to probe the chromospheric line-of-sight (LOS) magnetic field ($B_{\mathrm{LOS}}$) by comparing the $B_{\mathrm{LOS}}$ inferred from the weak field…

Solar and Stellar Astrophysics · Physics 2023-04-05 Harsh Mathur , K. Nagaraju , Jayant Joshi , Jaime de la Cruz Rodríguez

Zeeman observations provide the only direct probe of line-of-sight (LOS) magnetic fields in the interstellar medium. To evaluate their accuracy and limitations, we generate synthetic HI Zeeman spectra from magnetohydrodynamic simulations…

Astrophysics of Galaxies · Physics 2026-02-24 Duo Xu , Peter Martin , Stella Offner , Robert Gutermuth , Michael Grudic , Joshua Speagle

We explore the diagnostic potential of the H$\alpha$ line for probing the chromospheric magnetic field using a realistic 3D radiative magnetohydrodynamic (rMHD) model. The Stokes profiles of the H$\alpha$ line are synthesized through full…

Solar and Stellar Astrophysics · Physics 2025-07-08 Harsh Mathur , Jayant Joshi , Thore Espedal Moe , Tiago M. D. Pereira , K. Nagaraju

Aims. We examined the capabilities of methods based on the weak-field approximation and line bisectors to extract fast and reliable information about the height stratification of the magnetic field and line-of-sight velocities,…

Solar and Stellar Astrophysics · Physics 2025-03-18 A. L. Siu-Tapia , L. R. Bellot Rubio , D. Orozco Suárez

Aims. We aim to infer information about the magnetic field in the low solar corona from coronal rain clumps using high-resolution spectropolarimetric observations in the Ca ii 8542 A line obtained with the Swedish 1-m Solar Telescope.…

Solar and Stellar Astrophysics · Physics 2021-06-09 M. Kriginsky , R. Oliver , P. Antolin , D. Kuridze , N. Freij

Context. A proper estimate of the chromospheric magnetic fields is believed to improve modelling of both active region and coronal mass ejection evolution. Aims. We investigate the similarity between the chromospheric magnetic field…

The magnetic line ratio (MLR) method has been extensively used in the measurement of photospheric magnetic field strength. It was devised for the neutral iron line pair at 5247.1 A and 5250.2 A (5250 A pair). Other line pairs as well-suited…

Solar and Stellar Astrophysics · Physics 2017-12-13 H. N. Smitha , S. K. Solanki

We study the quiet Sun magnetic fields using spectropolarimetric observations of the infrared and visible Fe I lines at 6301.5, 6302.5, 15648 and 15653 A. Magnetic field strengths and filling factors are inferred by the simultaneous fit of…

Astrophysics · Physics 2008-11-26 Itahiza Dominguez Cerdena , Jorge Sanchez Almeida , Franz Kneer

This study based on longitudinal Zeeman effect magnetograms and spectral line scans investigates the dependence of solar surface magnetic fields on the spectral line used and the way the line is sampled in order to estimate the magnetic…

Astrophysics · Physics 2009-11-13 R. K. Ulrich , L. Bertello , J. E. Boyden , L. Webster

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

The spectral window, containing Fraunhofer lines formed in the solar photosphere, around the magnetically sensitive Cr I lines at 5780.9, 5781.1, 5781.7, 5783.0, and 5783.8 \r{A}, with Land\'e g-factors between 1.6 and 2.5, is explored. The…

We analyze spectropolarimetric observations of the chromospheric Ca II 8542 A line taken by the Interferometric Bidimensional Spectrometer (IBIS) at the Dunn Solar Telescope. The data were observed on 2012 January 29 for the NOAA active…

Solar and Stellar Astrophysics · Physics 2017-12-20 Ali G. A. Abdelkawy , Abdelrazek M. K. Shaltout , M. M. Beheary , T. A. Schad

The Chromospheric LAyer SpectroPolarimeter missions, CLASP2 and CLASP2.1, demonstrated that the near-UV spectral region between 279.30 and 280.68 nm is suitable for studying the magnetism of the solar chromosphere. In particular, the…

The goal of this study is to explore a novel method for the solar photospheric magnetic field diagnostics using Stokes V widths of different magnetosensitive Fe~I spectral lines. We calculate Stokes I and V profiles of several Fe I lines…

Solar and Stellar Astrophysics · Physics 2020-01-29 M. Gordovskyy , S. Shelyag , P. K. Browning , V. G. Lozitsky

The Mg I b$_2$ line at 5173 \r{A} is primarily magnetically sensitive to heights between the mid photosphere and the low chromosphere, a region that has not been sufficiently explored in the solar atmosphere but is crucial for understanding…

Solar and Stellar Astrophysics · Physics 2025-03-18 A. L. Siu-Tapia , L. R. Bellot Rubio , D. Orozco Suárez , R. Gafeira

Early magnetographic observations indicated that magnetic field in the solar photosphere has unresolved small-scale structure. Near-infrared and optical data with extremely high spatial resolution show that these structures have scales of…

Solar and Stellar Astrophysics · Physics 2018-11-21 M. Gordovskyy. , S. Shelyag , P. K. Browning , V. G. Lozitsky
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