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Models for the evolution of the solar coronal magnetic field are vital for understanding solar activity, yet the best measurements of magnetic field lie at the photosphere, necessitating the development of coronal models which are…

Solar and Stellar Astrophysics · Physics 2017-04-05 James E. Leake , Mark G. Linton , Peter W. Schuck

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

Seven different models are applied to the same problem of simulating the Sun's coronal magnetic field during the solar eclipse on 2015 March 20. All of the models are non-potential, allowing for free magnetic energy, but the associated…

The internal dynamics of the Sun generate magnetic and plasma structures in the photosphere and overlying atmosphere across a wide range of spatial scales. Identifying the critical spatial scale is essential for interpreting physical…

Solar and Stellar Astrophysics · Physics 2026-04-14 Ananya Hore , Prantika Bhowmik

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

We present a careful assess of the forced field extrapolation using Solar Dynamics Observatory/Helioseismic and Magnetic Imager (SDO/HMI) magnetogram. The convergence property is checked by several metrics. The extrapolated field lines…

Solar and Stellar Astrophysics · Physics 2017-03-22 Xiaoshuai Zhu , Huaning Wang , Zhanle Du , Han He

Observations suggest a power-law relation between the coronal emission in X-rays, $L_{\rm{X}}$, and the total (unsigned) magnetic flux at the stellar surface, $\Phi$. The physics basis for this relation is poorly understood. We use…

Solar and Stellar Astrophysics · Physics 2021-08-04 J. Zhuleku , J. Warnecke , H. Peter

Using turbulent MHD simulations (magnetic Reynolds numbers up to 8000) and Hinode observations, we study effects of turbulence on measuring the solar magnetic field outside active regions. Firstly, from synthetic Stokes V profiles for the…

Astrophysics · Physics 2011-02-11 Jonathan Pietarila Graham , Sanja Danilovic , Manfred Schuessler

Sigmoids produce strong eruptive events. Earlier studies have shown that the ICME axial magnetic field Bz can be predicted with some credibility by observing the corresponding filament or the polarity inversion line in the region of…

Solar and Stellar Astrophysics · Physics 2024-03-27 V. Aparna , Manolis K. Georgoulis , Petrus C. Martens

The measurement of the Sun's surface motions with a high spatial and temporal resolution is still a challenge. We wish to validate horizontal velocity measurements all over the visible disk of the Sun from Solar Dynamics Observatory/…

Solar and Stellar Astrophysics · Physics 2015-06-15 Th. Roudier , M. Rieutord , V. Prat , J. M. Malherbe , N. Renon , Z. Frank , M. Svanda , T. Berger , R. Burston , L. Gizon

A nonlinear force-free solution is constructed for the coronal magnetic field in NOAA solar active region AR 10953 based on a photospheric vector magnetogram derived from Hinode satellite observations on 30 April 2007, taking into account…

Solar and Stellar Astrophysics · Physics 2015-05-20 M. S. Wheatland , K. D. Leka

Numerical MHD simulations of 3D reconnection events in the solar corona have improved enormously over the last few years, not only in resolution, but also in their complexity, enabling more and more realistic modeling. Various ways to…

Solar and Stellar Astrophysics · Physics 2012-11-07 G. Baumann , K. Galsgaard , Å. Nordlund

Context. On the sun, the magnetic field vector is measured routinely only in the photosphere. By using these photospheric measurements as boundary condition, we developed the magnetohydrostatic (MHS) extrapolation to model the solar…

Solar and Stellar Astrophysics · Physics 2019-11-20 Xiaoshuai Zhu , Thomas Wiegelmann

Coronal magnetic fields evolve quasi statically over long time scales and dynamically over short time scales. As of now there exists no regular measurements of coronal magnetic fields, and therefore generating the coronal magnetic field…

Solar and Stellar Astrophysics · Physics 2023-12-20 P. Vemareddy , Jörn Warnecke , Ph. A. Bourdin

Time-dependent three-dimensional magnetohydrodynamics (MHD) simulation modules are implemented at the Joint Science Operation Center (JSOC) of Solar Dynamics Observatory (SDO). The modules regularly produce three-dimensional data of the…

Solar and Stellar Astrophysics · Physics 2015-04-22 Keiji Hayashi , J. Todd Hoeksema , Yang Liu , Monica G. Bobra , Xudong D. Sun , Aimee A. Norton

Nonlinear force-free solutions for the magnetic field in the solar corona constructed using photospheric vector magnetic field boundary data suffer from a basic problem: the observed boundary data are inconsistent with the nonlinear…

Solar and Stellar Astrophysics · Physics 2009-07-22 M. S. Wheatland , S. Regnier

AIMS :The thermodynamic and magnetic field structure of the solar photosphere is analyzed by means of a novel 3-dimensional spectropolarimetric inversion and reconstruction technique. METHODS : On the basis of high-resolution,…

Astrophysics · Physics 2008-03-10 T. A. Carroll , M. Kopf

In the past, spectropolarimetric data from Hinode/SP has been employed to infer the distribution of the magnetic field vector in the quiet Sun. While some authors have found predominantly horizontal magnetic fields, others favor an…

Solar and Stellar Astrophysics · Physics 2015-05-20 J. M. Borrero , P. Kobel

We investigate the orientation of the photospheric magnetic fields in the solar polar region using observations from the Helioseismic and Magnetic Imager (HMI). Inside small patches of significant polarization, the inferred magnetic field…

Solar and Stellar Astrophysics · Physics 2021-06-04 Xudong Sun , Yang Liu , Ivan Milić , Ana Belén Griñón Marín

Duo to the large magnetic Reynolds number, the magnetic helicity originating from the solar interior can be carried away through the photosphere into the corona. However, the relationship between the accumulated magnetic helicity flux…

Solar and Stellar Astrophysics · Physics 2022-04-27 Quan Wang , Shangbin Yang , Mei Zhang , Xiao Yang