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Magnetograms from the Vector SpectroMagnetograph (VSM) of the Synoptic Optical Long-term Investigations of the Sun (SOLIS) project are utilized to study the latitude distribution of magnetic flux elements as a function of latitude in the…

Astrophysics · Physics 2008-01-03 N. -E. Raouafi , J. W. Harvey , C. J. Henney

The solar atmosphere is extremely dynamic, and many important phenomena develop on small scales that are unresolved in observations with the Helioseismic and Magnetic Imager (HMI) instrument on the Solar Dynamics Observatory (SDO). For…

Solar and Stellar Astrophysics · Physics 2015-08-06 Irina N. Kitiashvili , Sebastien Couvidat , Andreas Lagg

Photospheric magnetic vector maps from two different instruments are used to model the nonlinear force-free coronal magnetic field above an active region. We use vector maps inferred from polarization measurements of the Solar Dynamics…

Solar and Stellar Astrophysics · Physics 2015-06-15 J. K. Thalmann , S. K. Tiwari , T. Wiegelmann

This study based on longitudinal Zeeman effect magnetograms and spectral line scans investigates the dependence of solar surface magnetic fields on the spectral line used and the way the line is sampled in order to estimate the magnetic…

Astrophysics · Physics 2009-11-13 R. K. Ulrich , L. Bertello , J. E. Boyden , L. Webster

The line-of-sight (LOS) component of the large-scale photospheric magnetic field has been observed since the 1950s, but the daily full-disk observations of the full vector magnetic field started only in 2010 using the SOLIS Vector Stokes…

Space Physics · Physics 2019-04-25 Ilpo I. Virtanen , Alexei A. Pevtsov , Kalevi Mursula

Line-of-sight magnetograms from the Helioseismic and Magnetic Imager (HMI) of the Solar Dynamics Observatory (SDO) are analyzed using a diagnostic known as the "Magnetic Range of Influence," or MRoI. The MRoI is a measure of the length over…

Solar and Stellar Astrophysics · Physics 2015-06-19 Scott W. McIntosh , Xin Wang , Robert J. Leamon , Philip H. Scherrer

The Helioseismic and Magnetic Imager (HMI) began near-continuous full-disk solar measurements on 1 May 2010 from the Solar Dynamics Observatory (SDO). An automated processing pipeline keeps pace with observations to produce observable…

Large-scale velocity fields in the solar photosphere remain a mystery in spite of many years of intensive studies. In this thesis, the new method of the measurements of the solar photospheric flow fields is proposed. It is based on local…

Astrophysics · Physics 2007-12-13 Michal Svanda

Comparisons of solar magnetic-field measurements made in different spectral lines are very important, especially in those lines in which observations have a long history or(and) specific diagnostic significance. The spectral lines FeI 523.3…

Solar and Stellar Astrophysics · Physics 2009-12-18 Michael L. Demidov , Horst Balthasar

In this dataset we provide a comprehensive collection of magnetograms (images quantifying the strength of the magnetic field) from the National Aeronautics and Space Administration's (NASA's) Solar Dynamics Observatory (SDO). The dataset…

Solar and Stellar Astrophysics · Physics 2024-02-13 Laura E. Boucheron , Ty Vincent , Jeremy A. Grajeda , Ellery Wuest

The Helioseismic and Magnetic Imager (HMI) provides continuum images and magnetograms with a cadence better than one per minute. It has been continuously observing the Sun 24 hours a day for the past 7 years. The obvious trade-off between…

Solar and Stellar Astrophysics · Physics 2018-06-06 C. J. Diaz Baso , A. Asensio Ramos

NASA's Solar Dynamics Observatory (SDO) was launched 11 February 2010 with 3 instruments on board, including the Helioseismic and Magnetic Imager (HMI). Since beginning normal operations on 1 May 2010, HMI has observed the Sun's entire…

The average unsigned magnetic flux density in magnetograms of the quiet Sun is generally dominated by instrumental noise. Due to the entirely different scaling behavior of the noise and the solar magnetic pattern it has been possible to…

Solar and Stellar Astrophysics · Physics 2015-06-11 J. O. Stenflo

We study Doppler velocity measurements at multiple heights in the solar atmosphere using a set of six filtergrams obtained by the Helioseismic magnetic Imager on board the Solar Dynamics Observatory. There are clear and significant phase…

Solar and Stellar Astrophysics · Physics 2014-01-15 Kaori Nagashima , Laurent Gizon , Aaron Birch , Björn Löptien , Sebastien Couvidat , Bernhard Fleck

The Sun's axisymmetric flows, differential rotation and meridional flow, govern the dynamics of the solar magnetic cycle and variety of methods are used to measure these flows, each with its own strengths and weaknesses. Flow measurements…

Solar and Stellar Astrophysics · Physics 2021-09-08 Sushant S. Mahajan , David H. Hathaway , Andrés Muñoz-Jaramillo , Petrus C. Martens

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

As the global magnetic field of the Sun has an activity cycle, one expects to observe some variation of the dynamical properties of the flows visible in the photosphere. We investigate the flow field during the solar cycle by analysing…

Solar and Stellar Astrophysics · Physics 2017-02-15 Th. Roudier , J. M. Malherbe , G. M. Mirouh

Spectral analysis of the spatial structure of solar subphotospheric convection is carried out for subsurface flow maps constructed using the time--distance helioseismological technique. The source data are obtained from the Helioseismic and…

Solar and Stellar Astrophysics · Physics 2022-09-27 Alexander V. Getling , Alexander G. Kosovichev

The Vector Spectromagnetograph (VSM) instrument has been recording photospheric and chromospheric magnetograms daily since August 2003. Full-disk photospheric vector magnetograms are observed at least weekly and, since November 2006,…

The National Solar Observatory (NSO) Synoptic Optical Long-term Investigations of the Sun (SOLIS) Vector SpectroMagnetograph (VSM) is sealed and was designed to be filled with helium at slightly above ambient pressure. After 11 years of…

Instrumentation and Methods for Astrophysics · Physics 2014-06-02 J. W. Harvey