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Related papers: A nonlinear solar magnetic field calibration metho…

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It is widely believed that loops observed in the solar atmosphere trace out magnetic field lines. However, the degree to which magnetic field extrapolations yield field lines that actually do follow loops has yet to be studied…

Solar and Stellar Astrophysics · Physics 2018-06-27 Harry P. Warren , Nicholas A. Crump , Ignacio Ugarte-Urra , Xudong Sun , Markus J. Aschwanden , Thomas Wiegelmann

We take a broad look at the problem of identifying the magnetic solar causes of space weather. With the lackluster performance of extrapolations based upon magnetic field measurements in the photosphere, we identify a region in the near UV…

Magnetic field inhomogeneity estimation is important in some types of magnetic resonance imaging (MRI), including field-corrected reconstruction for fast MRI with long readout times, and chemical shift based water-fat imaging. Regularized…

Image and Video Processing · Electrical Eng. & Systems 2020-10-13 Claire Yilin Lin , Jeffrey A. Fessler

We derive an analytical approximation of nonlinear force-free magnetic field solutions (NLFFF) that can efficiently be used for fast forward-fitting to solar magnetic data, constrained either by observed line-of-sight magnetograms and…

Solar and Stellar Astrophysics · Physics 2014-03-27 Markus J. Aschwanden

Aims. Linear magnetohydrostatic (MHS) models of solar magnetic fields balance plasma pressure gradients, gravity and Lorentz forces where the current density is composed of a linear force-free component and a cross-field component that…

Solar and Stellar Astrophysics · Physics 2013-07-26 David MacTaggart , Abdulaziz Elsheikh , James McLaughlin , Radostin Simitev

The magnetic diagnostics subsystem of the LISA Technology Package (LTP) on board the LISA PathFinder (LPF) spacecraft includes a set of four tri-axial fluxgate magnetometers, intended to measure with high precision the magnetic field at…

General Relativity and Quantum Cosmology · Physics 2015-05-14 M Diaz-Aguilo , E Garcia-Berro , A Lobo

The physical interpretation of spectropolarimetric observations of lines of neutral helium, such as those of the 10830 A multiplet, represents an excellent opportunity for investigating the magnetism of plasma structures in the solar…

Astrophysics · Physics 2007-05-23 A. Asensio Ramos , J. Trujillo Bueno

We aim at demonstrating the capabilities of a newly developed method for determining electric currents in the solar photosphere. We employ three-dimensional radiative magneto-hydrodynamic (MHD) simulations to produce synthetic Stokes…

Solar and Stellar Astrophysics · Physics 2021-12-22 A. Pastor Yabar , J. M. Borrero , C. Quintero Noda , B. Ruiz Cobo

In this work, we study and quantify properties of strong-field small-scale convection and compare observed properties with those predicted by numerical simulations. We analyze spectropolarimetric 630.25 nm data from a unipolar ephemeral…

Solar and Stellar Astrophysics · Physics 2015-05-19 G. Narayan , G. B. Scharmer

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

To study the structure of spatially unresolved features of the solar photosphere, we calculated the Stokes profiles of seven photospheric iron lines using two-dimensional nonstationary MHD models of solar granulation for various amounts of…

Solar and Stellar Astrophysics · Physics 2012-11-13 I. N. Atroshchenko , V. A. Sheminova

We apply topological methods to better understand how the magnetic field in the stellarator edge can be diverted away from the confined region. Our primary method is calculating the winding numbers of closed contours, which gives…

We present the design concept of the wavelength calibration system for the Habitable-zone Planet Finder instrument (HPF), a precision radial velocity (RV) spectrograph designed to detect terrestrial-mass planets around M-dwarfs. HPF is a…

Instrumentation and Methods for Astrophysics · Physics 2014-08-19 Samuel Halverson , Suvrath Mahadevan , Lawrence Ramsey , Ryan Terrien , Arpita Roy , Christian Schwab , Chad Bender , Fred Hearty , Eric Levi , Steve Osterman , Gabe Ycas , Scott Diddams

Integral Field Spectrographs (IFS) often require non-trivial calibration techniques to process raw data. The OH Suppressing InfraRed Imaging Spectrograph (OSIRIS) at the W. M. Keck Observatory is a lenslet-based IFS that requires precise…

Instrumentation and Methods for Astrophysics · Physics 2022-07-06 Katelyn Horstman , Michael P. Fitzgerald , James E. Lyke , Sherry C. C. Yeh , Devin S. Chu

The imaging spectro-polarimeter VTF (Visible Tunable Filter) will be operated at the Daniel K. Inouye Solar Telescope (DKIST). Due to its capability of resolving dynamic fine structure of smaller than 0.05'', the finite acquisition time of…

Solar and Stellar Astrophysics · Physics 2023-01-18 Rolf Schlichenmaier , Daniel Pitters , Juan Manuel Borrero , Matthias Schubert

Since the first detection of gravitational waves by the LIGO/VIRGO team, the related research field has attracted more attention. The spinning compact binaries system, as one of the gravitational-wave sources for broadband laser…

General Relativity and Quantum Cosmology · Physics 2022-12-21 Junjie Luo , Jie Feng , Hong-Hao Zhang , Weipeng Lin

We investigate the possibility of measuring magnetic field strength in G-band bright points through the analysis of Zeeman polarization in molecular CH lines. To this end we solve the equations of polarized radiative transfer in the G band…

Astrophysics · Physics 2009-11-10 H. Uitenbroek , E. Miller-Ricci , A. Asensio Ramos , J. Trujillo Bueno

Extrapolation codes in Cartesian geometry for modelling the magnetic field in the corona do not take the curvature of the Sun's surface into account and can only be applied to relatively small areas, e.g., a single active region. We compare…

Solar and Stellar Astrophysics · Physics 2015-06-11 Tilaye Tadesse , T. Wiegelmann , B. Inhester , P. MacNeice , A. Pevtsov , X. Sun

We present results from the analysis of Fe I 630 nm measurements of the quiet Sun taken with the spectropolarimeter of the Hinode satellite. Two data sets with noise levels of 1.2{\times}10-3 and 3{\times}10-4 are employed. We determine the…

Solar and Stellar Astrophysics · Physics 2015-06-04 D. Orozco Suárez , L. R. Bellot Rubio

Accurate modeling of the Sun's coronal magnetic field and solar wind structures require inputs of the solar global magnetic field, including both the near and far sides, but the Sun's far-side magnetic field cannot be directly observed.…

Solar and Stellar Astrophysics · Physics 2023-01-04 Ruizhu Chen , Junwei Zhao , Shea Hess Webber , Yang Liu , J. Todd Hoeksema , Marc L. Derosa
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