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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

Spectral inversion codes are powerful tools to analyze spectropolarimetric observations, and they provide important diagnostics of solar magnetic fields. Inversion codes differ by numerical procedures, approximations of the atmospheric…

Solar and Stellar Astrophysics · Physics 2015-06-04 H. Balthasar , M. L. Demidov

Stack filters are a special case of non-linear filters. They have a good performance for filtering images with different types of noise while preserving edges and details. A stack filter decomposes an input image into stacks of binary…

Computer Vision and Pattern Recognition · Computer Science 2013-06-11 María Elena Buemi , Alejandro C. Frery , Heitor S. Ramos

The magnetic topology of the solar photosphere in its quietest regions is hidden by the difficulties to disentangle magnetic flux through the resolution element from the field strength of unresolved structures. The observation of spectral…

Astrophysics · Physics 2015-05-13 J. C. Ramirez Velez , A. Lopez Ariste , M. Semel

We present a method for absolute calibration of received radio-frequency in the ultra low frequency (ULF), and very low frequency (VLF) range. This is achieved with the use of a radio frequency optically pumped magnetometer (RF-OPM). We…

We developed a new nonlinear force-free magnetic field (NLFFF) forward-fitting algorithm based on an analytical approximation of force-free and divergence-free NLFFF solutions, which requires as input a line-of-sight magnetogram and traced…

Solar and Stellar Astrophysics · Physics 2013-05-24 Markus J. Aschwanden

Multiline techniques assuming similar line profiles have become a standard tool in stellar astronomy for increasing the signal-to-noise ratio (SNR) of spectropolarimetric measurements. However, due to the widely-used weak field…

Solar and Stellar Astrophysics · Physics 2010-03-29 C. Sennhauser , S. V. Berdyugina

Getting insights into the 3D structure of the solar coronal magnetic field have been done in the past by two completely different approaches: (1.) Nonlinear force-free field (NLFFF) extrapolations, which use photospheric vector magnetograms…

Solar and Stellar Astrophysics · Physics 2017-09-20 Iulia Chifu , Thomas Wiegelmann , Bernd Inhester

We present a method for calibrating the response of a phase-only spatial light modulator in nonlinear microscopy. Our method uses the microscope image itself as calibration measurement and requires no additional hardware components. Our…

Optics · Physics 2025-09-04 Daniël W. S. Cox , Harish Sasikumar , Ivo M. Vellekoop

We apply the vectorized Non-negative Matrix Factorization (NMF) method to post-processing of direct imaging data for exoplanetary systems such as circumstellar disks. NMF is an iterative approach, which first creates a non-orthogonal and…

Instrumentation and Methods for Astrophysics · Physics 2018-03-20 Bīn Rén , Laurent Pueyo , Guangtun Ben Zhu , John Debes , Gaspard Duchêne

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

We present a pipeline that allows recovering reliable information for all four Stokes parameters with high accuracy. Its novelty relies on the treatment of the instrumental effects already prior to the computation of the Stokes parameters…

Instrumentation and Methods for Astrophysics · Physics 2018-01-10 I. Myserlis , E. Angelakis , A. Kraus , C. A. Liontas , N. Marchili , M. F. Aller , H. D. Aller , V. Karamanavis , L. Fuhrmann , T. P. Krichbaum , J. A. Zensus

We study the predictive capabilities of magnetic feature properties (MF) generated by Solar Monitor Active Region Tracker (SMART) for solar flare forecasting from two datasets: the full dataset of SMART detections from 1996 to 2010 that has…

Solar and Stellar Astrophysics · Physics 2018-12-07 Katarina Domijan , D. Shaun Bloomfield , Francois Pitie

Polarized magnetic dipole (M1) emission lines provide important diagnostics for the magnetic field dominating the evolution of the solar corona. This paper advances a multi-line technique using specific combinations of M1 lines to infer the…

Solar and Stellar Astrophysics · Physics 2020-02-12 Gabriel I. Dima , Thomas A. Schad

We present test results on the simultaneous inversion of the Stokes profiles of the He I lines at 587.6 nm (D_3) and 1083.0 nm in prominences (90-deg scattering). We created datasets of synthetic Stokes profiles for the case of quiescent…

Instrumentation and Methods for Astrophysics · Physics 2009-09-28 R. Casini , A. Lopez Ariste , F. Paletou , L. Leger

Solar panel mapping has gained a rising interest in renewable energy field with the aid of remote sensing imagery. Significant previous work is based on fully supervised learning with classical classifiers or convolutional neural networks…

Image and Video Processing · Electrical Eng. & Systems 2021-03-18 Jue Zhang , Xiuping Jia , Jiankun Hu

Accurately measuring magnetic fields is essential for magnetic-field sensitive experiments in fields like atomic, molecular, and optical physics, condensed matter experiments, and other areas. However, since many experiments are conducted…

Instrumentation and Detectors · Physics 2023-05-31 Ziting Chen , Kin To Wong , Bojeong Seo , Mingchen Huang , Mithilesh K. Parit , Haoting Zhen , Jensen Li , Gyu-Boong Jo

Context. A significant part of the penumbral magnetic field returns below the surface in the very deep photosphere. For lines in the visible, a large portion of this return field can only be detected indirectly by studying its imprints on…

We develop a practical forward fitting method based on the SIMPLEX algorithm with shaking, which allows the derivation of the magnetic field and other parameters along a solar flaring loop using microwave imaging spectroscopy of…

Solar and Stellar Astrophysics · Physics 2011-02-11 Gregory D. Fleishman , Gelu M. Nita , Dale E. Gary

This paper presents a large-scale strip adjustment method for LiDAR mobile mapping data, yielding highly precise maps. It uses several concepts to achieve scalability. First, an efficient graph-based pre-segmentation is used, which directly…

Distributed, Parallel, and Cluster Computing · Computer Science 2016-09-27 Claus Brenner
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