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Routine measurements of the solar magnetic field are mainly carried out in the photosphere. Therefore, one has to infer the field strength in the higher layers of the solar atmosphere from the measured photospheric field based on the…

Solar and Stellar Astrophysics · Physics 2015-05-20 Tilaye Tadesse , T. Wiegelmann , B. Inhester , A. Pevtsov

When inverting solar spectra, image degradation effects that are present in the data are usually approximated or not considered. We develop a data reduction method that takes these issues into account and minimizes the resulting errors. By…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 M. van Noort

Static electric response properties of atoms and molecules are reported within the real-space Cartesian grid implementation of pseudopotential Kohn-Sham (KS) density functional theory (DFT). A detailed systematic investigation is made for a…

Chemical Physics · Physics 2019-04-26 Tanmay Mandal , Abhisek Ghosal , Amlan K. Roy

Full-disk measurements of the solar magnetic field by the Helioseismic and Magnetic Imager (HMI) are often used for magnetic field extrapolations, but its limited spatial and spectral resolution can lead to significant errors. We compare…

Solar and Stellar Astrophysics · Physics 2024-11-27 C. Beck , A. Prasad , Q. Hu , M. S. Yalim , S. Gosain , D. P. Choudhary

Photonic Doppler Velocimetry (PDV) is an established technique for measuring the velocities of fast-moving surfaces in high-energy-density experiments. In the standard approach to PDV analysis, a short-time Fourier transform (STFT) is used…

The potential field source surface (PFSS) method is a widely used magnetic field extrapolation technique in the space weather community. The only free parameter in the PFSS method is the source-surface height ($R_{\rm SS}$), beyond which…

Solar and Stellar Astrophysics · Physics 2025-10-16 Munehito Shoda , Kyogo Tokoro , Daikou Shiota , Shinsuke Imada

A spectral line inversion code, Very Fast Inversion of the Stokes Vector (VFISV), has been used since May 2010 to infer the solar atmospheric parameters from the spectropolarimetric observations taken by the Helioseismic and Magnetic Imager…

Solar and Stellar Astrophysics · Physics 2021-12-22 Ana Belén Griñón-Marín , Adur Pastor Yabar , Yang Liu , J. Todd Hoeksema , Aimee Norton

The Full-disk magnetograph is a main scientific payload onboard the Advanced Space based Solar Observatory (ASO-S/FMG) that through Stokes parameter observation to measures the vector magnetic field. The accuracy of magnetic-field values is…

Solar and Stellar Astrophysics · Physics 2023-12-04 S. Liu , J. T. Su , X. Y. Bai , Y. Y. Deng , J. Chen , Y. L. Song , X. F. Wang , H. Q. Xu , X. Yang

The observed solar photospheric magnetic fields and Doppler velocities are frequently used to quantify the Poynting flux and helicity flux. Multiple methods have been developed for this purpose, but their estimates of the Poynting flux and…

Solar and Stellar Astrophysics · Physics 2026-04-20 Jiayi Liu , Xudong Sun , Peter W. Schuck , Lars K. S. Daldorff

Spectropolarimetric inversions are routinely used in the field of Solar Physics for the extraction of physical information from observations. The application to two-dimensional fields of view often requires the use of supercomputers with…

Solar and Stellar Astrophysics · Physics 2019-06-26 A. Asensio Ramos , C. Diaz Baso

The iodine-cell technique, which is known to be efficient in precisely establishing Doppler velocity shifts, was once applied by the author to measuring the solar differential rotation based on full-disk spectroscopic observations (Takeda…

Solar and Stellar Astrophysics · Physics 2024-06-27 Yoichi Takeda

Recently it was reported that deeply subwavelength features of free space superoscillatory electromagnetic fields can be observed experimentally and used in optical metrology with nanoscale resolution [Science 364, 771 (2019)]. Here we…

Optics · Physics 2019-10-08 T. Pu , V. Savinov , G. Yuan , N. Papasimakis , N. I. Zheludev

Plages are small concentrations of strong, nearly vertical magnetic fields in the solar photosphere that expand with height. A high spatial and spectral resolution that can resolve their fine structure is required to characterize them, and…

Solar and Stellar Astrophysics · Physics 2025-05-13 G. Liu , I. Milić , J. S. Castellanos Duran , J. M. Borrero , M. van Noort , C. Kuckein

An accurate solar wind speed model is important for space weather predictions, catastrophic event warnings, and other issues concerning solar wind - magnetosphere interaction. In this work, we construct a model based on convolutional neural…

Solar and Stellar Astrophysics · Physics 2023-04-05 Rong Lin , Zhekai Luo , Jiansen He , Lun Xie , Chuanpeng Hou , Shuwei Chen

Inversion techniques applied to the radiative transfer equation for polarized light are capable of inferring the physical parameters in the solar atmosphere (temperature $T$, magnetic field ${\bf B}$, and line-of-sight velocity $v_{\rm…

Solar and Stellar Astrophysics · Physics 2021-04-07 J. M. Borrero , A. Pastor Yabar , B. Ruiz Cobo

We have undertaken a major enhancement of our IDL-based simulation tools developed earlier for modeling microwave and X-ray emission. The object-based architecture provides an interactive graphical user interface that allows the user to…

Solar and Stellar Astrophysics · Physics 2015-06-22 Gelu M. Nita , Gregory D. Fleishman , Alexey A. Kuznetsov , Eduard P. Kontar , Dale E. Gary

The measurement of solar magnetic fields using the Zeeman effect diagnostics has a fundamental 180 degree ambiguity in the determination of the azimuth angle of the transverse field component. There are several methods that are used in the…

Solar and Stellar Astrophysics · Physics 2015-06-11 Sanjay Gosain , Alexei A. Pevtsov

We present a systematic, quasi-automated methodology for generating electronic models in the framework of second-principles density functional theory (SPDFT). This approach enables the construction of accurate and computationally efficient…

In many areas of science and engineering, it is a common task to infer physical fields from sparse observations. This paper presents the DAFI code intended as a flexible framework for two broad classes of such inverse problems: data…

Computational Physics · Physics 2020-12-07 Carlos A. Michelén Ströfer , Xin-Lei Zhang , Heng Xiao

Recently, we have developed a method useful for mapping large-scale horizontal velocity fields in the solar photosphere. The method was developed, tuned and calibrated using the synthetic data. Now, we applied the method to the series of…

Astrophysics · Physics 2009-11-13 Michal Svanda , Mirek Klvana , Michal Sobotka , Vaclav Bumba