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Related papers: A new MHD-assisted Stokes inversion technique

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Seismic imaging is the numerical process of creating a volumetric representation of the subsurface geological structures from elastic waves recorded at the surface of the Earth. As such, it is widely utilized in the energy and construction…

Geophysics · Physics 2024-11-05 Juan Romero , Wolfgang Heidrich , Nick Luiken , Matteo Ravasi

The magnetic field plays a major role in governing the dynamics of the sun. Many interesting features like sunspots, flares, prominences, and Coronal Mass Ejections (CMEs) occur on its surface due to the dynamics associated with the…

Instrumentation and Methods for Astrophysics · Physics 2016-12-14 Souvik Bose

This paper presents an overview and introduction to Smoothed Particle Hydrodynamics and Magnetohydrodynamics in theory and in practice. Firstly, we give a basic grounding in the fundamentals of SPH, showing how the equations of motion and…

Instrumentation and Methods for Astrophysics · Physics 2010-12-22 Daniel J. Price

Interpreting the Stokes profiles observed in quiet regions of the solar chromosphere is a challenging task. The Stokes Q and U profiles are dominated by the scattering polarisation and the Hanle effect, and these processes can only be…

Solar and Stellar Astrophysics · Physics 2018-11-07 Jan Jurcak , Jiri Stepan , Javier Trujillo Bueno , Michele Bianda

In this paper we apply the recently developed mimetic discretization method to the mixed formulation of the Stokes problem in terms of vorticity, velocity and pressure. The mimetic discretization presented in this paper and in [50] is a…

Numerical Analysis · Mathematics 2015-06-03 Jasper Kreeft , Marc Gerritsma

A finite difference numerical scheme is proposed and analyzed for the Cahn-Hilliard-Stokes system with Flory-Huggins energy functional. A convex splitting is applied to the chemical potential, which in turns leads to the implicit treatment…

Numerical Analysis · Mathematics 2023-03-22 Yunzhuo Guo , Cheng Wang , Steven M. Wise , Zhengru Zhang

HII regions powered by ionizing radiation from massive stars drive the dynamical evolution of the interstellar medium. Fast radiative transfer methods for incorporating photoionization effects are thus essential in astrophysical…

Instrumentation and Methods for Astrophysics · Physics 2025-02-25 Cheryl S. C. Lau , Maya A. Petkova , Ian A. Bonnell

In this paper we propose an inversion strategy for the analysis of spectropolarimetric measurements taken by {\em Hinode} in the quiet Sun. The spectropolarimeter of the Solar Optical Telescope aboard {\em Hinode} records the Stokes spectra…

This paper describes the recently developed mixed mimetic spectral element method for the Stokes problem in the vorticity-velocity-pressure formulation. This compatible discretization method relies on the construction of a conforming…

Numerical Analysis · Computer Science 2012-06-14 Jasper Kreeft , Marc Gerritsma

Inversion codes are computer programs that fit a model atmosphere to the observed Stokes spectra, thus retrieving the relevant atmospheric parameters. The rising interest in the solar chromosphere, where spectral lines are formed by…

Solar and Stellar Astrophysics · Physics 2018-09-26 Ivan Milic , Michiel van Noort

We present the first interpretation of the Stokes profile asymmetries measured in the FeI 630 nm lines by SOT/SP, in both quiet Sun internetwork (IN) and network regions. The inversion is carried out under the hypothesis of MISMA, where the…

Solar and Stellar Astrophysics · Physics 2015-05-20 B. Viticchié , J. , Sánchez Almeida , D. Del Moro , F. Berrilli

Set representations are the foundation of various set-based approaches in state estimation, reachability analysis and fault diagnosis. In this paper, we investigate spectrahedral shadows, a class of nonlinear geometric objects previously…

Systems and Control · Electrical Eng. & Systems 2025-04-15 Chengrui Wang , Haohao Qiu , Sibo Yao , James Lam

We have studied the angular distribution of the magnetic field vector in the solar internetwork employing high-quality data (noise level $\sigma \approx 3\times 10^{-4}$ in units of the quiet-Sun intensity) at different latitudes recorded…

Solar and Stellar Astrophysics · Physics 2015-06-12 J. M. Borrero , P. Kobel

Recently, experiments have been reported where researchers were able to perform high dynamic range (HDR) tomography in a heuristic fashion, by fusing multiple tomographic projections. This approach to HDR tomography has been inspired by HDR…

Information Theory · Computer Science 2021-05-11 Matthias Beckmann , Ayush Bhandari , Felix Krahmer

The question is addressed to what extent incompressible magnetohydrodynamics (MHD) can describe random magnetic and velocity fluctuations measured in the solar wind. It is demonstrated that distributions of spectral indices for the…

Astrophysics of Galaxies · Physics 2015-05-28 Stanislav Boldyrev , Jean Carlos Perez , Joseph E. Borovsky , John J. Podesta

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

AIMS :The thermodynamic and magnetic field structure of the solar photosphere is analyzed by means of a novel 3-dimensional spectropolarimetric inversion and reconstruction technique. METHODS : On the basis of high-resolution,…

Astrophysics · Physics 2008-03-10 T. A. Carroll , M. Kopf

This paper introduces a novel feature extraction technique for the analysis of spectral line Stokes profiles. The procedure is based on the use of an auto-associative artificial neural network containing non-linear hidden layers. The neural…

Astrophysics · Physics 2009-11-10 H. Socas-Navarro

The ability of new instruments for providing accurate inferences of vector magnetic fields and line-of-sight velocities of the solar plasma depends a great deal on the sensitivity to these physical quantities of the spectral lines chosen to…

Solar and Stellar Astrophysics · Physics 2010-02-16 J. C. del Toro Iniesta , D. Orozco Suárez , L. R. Bellot Rubio

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
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