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Related papers: A new MHD-assisted Stokes inversion technique

200 papers

We study the presence of reversed polarity magnetic flux in sunspot penumbra. We applied a new regularized method to deconvolve spectropolarimetric data observed with the spectropolarimeter SP onboard Hinode. The new regularization is based…

Solar and Stellar Astrophysics · Physics 2015-06-12 B. Ruiz Cobo , A. Asensio Ramos

The numerical computation of reliable and accurate Stokes profiles is of great relevance in solar physics. In the synthesis process, many actors play a relevant role: among them the formal solver, the discrete atmospheric model, and the…

Solar and Stellar Astrophysics · Physics 2018-09-19 Gioele Janett , Oskar Steiner , Luca Belluzzi

This work aims to identify the relevant physical processes in shaping the intensity and polarization patterns of the solar K I D lines through spectral syntheses, placing particular emphasis on the D2 line. The theoretical Stokes profiles…

Solar and Stellar Astrophysics · Physics 2022-08-26 Ernest Alsina Ballester

Under mild conditions, it is possible to obtain, from almost purely measure-theoretic considerations and without any specific reference to stochastic processes, a change-of-measures result, resembling the usual Radon-Nikod\'ym change of…

Probability · Mathematics 2020-06-15 Yu-Lin Chou

A new three-dimensional model of the solar photosphere is presented in this paper and made publicly available to the community. This model has the peculiarity that it has been obtained by inverting spectro-polarimetric observations, rather…

Solar and Stellar Astrophysics · Physics 2015-05-27 H. Socas-Navarro

Knowledge of electric fields in the photosphere is required to calculate the electromagnetic energy flux through the photosphere and set up boundary conditions for data-driven magnetohydrodynamic (MHD) simulations of solar eruptions.…

Solar and Stellar Astrophysics · Physics 2021-09-22 Andrey N. Afanasyev , Maria D. Kazachenko , Yuhong Fan , George H. Fisher , Benoit Tremblay

Although the influence of magnetic fields is regarded as vital in the star formation process, only a few magnetohydrodynamics (MHD) simulations have been performed on this subject within the smoothed particle hydrodynamics (SPH) method.…

Solar and Stellar Astrophysics · Physics 2015-05-19 Florian Bürzle , Paul C. Clark , Federico Stasyszyn , Thomas Greif , Klaus Dolag , Ralf S. Klessen , Peter Nielaba

The polarization of the Mg II h & k resonance lines is the result of the joint action of scattering processes and the magnetic field induced Hanle, Zeeman, and magneto-optical effects, thus holding significant potential for the diagnostic…

Solar and Stellar Astrophysics · Physics 2024-09-10 Hao Li , Tanausú del Pino Alemán , Javier Trujillo Bueno

Mathematically rigorous inversion method is developed to recover compactly supported potentials from the fixed-energy scattering data in three dimensions. Error estimates are given for the solution. An algorithm for inversion of noisy…

Mathematical Physics · Physics 2007-05-23 A. G. Ramm

Based on magnetohydrodynamic turbulence simulations, we generate synthetic synchrotron observations to explore the scaling slope of the underlying MHD turbulence. We propose the new $Q$-$U$ cross intensity $X$ and cross-correlation…

High Energy Astrophysical Phenomena · Physics 2023-07-05 Zhang Xue-Wen , Zhang Jian-Fu , Wang Ru-Yue , Xiang Fu-Yuan

The efforts for comparing dust polarization measurements with synthetic observations from MHD models have previously concentrated on the scale of molecular clouds. Here we extend the model comparisons to kiloparsec scales, taking into…

Astrophysics of Galaxies · Physics 2018-06-27 Miikka S. Väisälä , Frederick A. Gent , Mika Juvela , Maarit J. Käpylä

Downscaling (DS) of meteorological variables involves obtaining high-resolution states from low-resolution meteorological fields and is an important task in weather forecasting. Previous methods based on deep learning treat downscaling as a…

Computer Vision and Pattern Recognition · Computer Science 2024-01-23 Zili Liu , Hao Chen , Lei Bai , Wenyuan Li , Keyan Chen , Zhengyi Wang , Wanli Ouyang , Zhengxia Zou , Zhenwei Shi

To obtain full Stokes spectra in multi-wavelength windows simultaneously, we developed a new spectro-polarimeter on the Domeless Solar Telescope at Hida Observatory. The new polarimeter consists of a 60 cm aperture vacuum telescope on an…

Instrumentation and Methods for Astrophysics · Physics 2018-06-13 Tetsu Anan , Yu Wei Huang , Yoshikazu Nakatani , Kiyoshi Ichimoto , Satoru Ueno , Goichi Kimura , Shota Ninomiya , Sanetaka Okada , Naoki Kaneda

In machine learning and statistical data analysis, we often run into objective function that is a summation: the number of terms in the summation possibly is equal to the sample size, which can be enormous. In such a setting, the stochastic…

Machine Learning · Statistics 2022-08-30 Yiling Luo , Xiaoming Huo , Yajun Mei

Point clouds can be regarded as discrete samples of smooth manifolds and are typically analyzed via the eigenfunctions of the Laplace-Beltrami operator. This paper extends manifold spectral analysis to the fractional domain, enabling…

General Mathematics · Mathematics 2026-05-04 Jiamian Li , Bing-Zhao Li

Response functions to perturbations in the temperature, pressure, microturbulent velocity, and magnetic intensity were calculated for the Stokes parameter profiles of the lines Fe I 525.06, 525.02 and Fe II 614.92 nm. The procedure proposed…

Solar and Stellar Astrophysics · Physics 2012-11-13 V. A. Sheminova

For the accurate representation and reconstruction of band-limited signals on the sphere, an optimal-dimensionality sampling scheme has been recently proposed which requires the optimal number of samples equal to the number of degrees of…

Information Theory · Computer Science 2017-09-11 Wajeeha Nafees , Zubair Khalid , Rodney A. Kennedy , Jason D. McEwen

4D seismic inversion is the leading method to quantitatively monitor fluid flow dynamics in the subsurface, with applications ranging from enhanced oil recovery to subsurface CO2 storage. The process of inverting seismic data for reservoir…

Geophysics · Physics 2023-10-25 Juan Romero , Nick Luiken , Matteo Ravasi

We have examined the spatial and polarimetric properties of these events using a variety of data from the Hinode spacecraft. We have also inferred the atmospheric stratification of the physical parameters by means of the inversion of the…

Solar and Stellar Astrophysics · Physics 2014-10-01 C. Quintero Noda , J. M. Borrero , D. Orozco Suárez , B. Ruiz Cobo

We compare Fourier spectra of photospheric velocity fields from very high resolution IMaX observations to those from recent 3D numerical magnetoconvection models. We carry out a proper comparison by synthesizing spectral lines from the…

Solar and Stellar Astrophysics · Physics 2015-06-18 L. Yelles Chaouche , F. Moreno-Insertis , J. A. Bonet