English
Related papers

Related papers: Comparison of force-free coronal magnetic field mo…

200 papers

In recent years, a two-dimensional (2D) coronal seismology technique applied to spectral-imaging data from the Coronal Multi-channel Polarimeter (CoMP) and UCoMP has enabled routine measurement of the global coronal magnetic field. The…

Solar and Stellar Astrophysics · Physics 2026-01-16 Zihao Yang , Sarah Gibson , Matthias Rempel , Giuliana de Toma

We discuss spectropolarimetric measurements of photospheric (Fe I 630.25 nm) and chromospheric (Ca II 854.21 nm) spectral lines. Our long-term goal is to diagnose properties of the magnetic field near the base of the corona. We compare…

Solar and Stellar Astrophysics · Physics 2015-05-14 P. G. Judge , A. Tritschler , H. Uitenbroek , G. Cauzzi , K. Reardon , A. de Wijn

The magnetic field governs the corona; hence it is a crucial parameter to measure. Unfortunately, existing techniques for estimating its strength are limited by strong assumptions and limitations. These techniques include photospheric or…

Solar and Stellar Astrophysics · Physics 2022-10-26 Juan Martinez-Sykora , Viggo H. Hansteen , Bart De Pontieu , Enrico Landi

Solar activity is usually caused by the evolution of solar magnetic fields. Magnetic field parameters derived from photospheric vector magnetograms of solar active regions have been used to analyze and forecast eruptive events such as solar…

Solar and Stellar Astrophysics · Physics 2023-07-26 Haodi Jiang , Qin Li , Zhihang Hu , Nian Liu , Yasser Abduallah , Ju Jing , Genwei Zhang , Yan Xu , Wynne Hsu , Jason T. L. Wang , Haimin Wang

Magneto-static models may overcome some of the issues facing force-free magnetic field extrapolations. So far they have seen limited use and have faced problems when applied to quiet-Sun data. Here we present a first application to an…

Direct solar coronal magnetic field measurements have become possible since recent development of high-sensitivity infrared detection technology. The SOLARC instrument installed on Mt. Haleakala is such a polarimetric coronagraph that was…

Astrophysics · Physics 2008-09-05 Y. Liu , H. Lin

We compared magnetograms from the KPVT/SPM, SoHO/MDI, SOLIS/VSM, and SDO/HMI with the aim of probing the effect on measured solar magnetism of the variation in instrument response with time, magnetogram signal level, and position on the…

Solar and Stellar Astrophysics · Physics 2024-05-24 K. L. Yeo , S. K. Solanki , N. A. Krivova

The plasma thermodynamics in the solar upper atmosphere, particularly in the corona, are dominated by the magnetic field, which controls the flow and dissipation of energy. The relative lack of knowledge of the coronal vector magnetic field…

Solar and Stellar Astrophysics · Physics 2016-06-29 N. E. Raouafi , P. Riley , S. Gibson , S. Fineschi , S. K. Solanki

The Potential Field Source Surface (PFSS) model is the most used approach for extrapolating the global coronal magnetic field, offering efficiency and strong performance at large scales. However, PFSS assumes a potential coronal field, so…

Solar and Stellar Astrophysics · Physics 2026-03-23 C. Antonio , I. Chifu , R. Gafeira , J. J. G. Lima

We estimated the accuracy of coronal magnetic fields derived from radio observations by comparing them to potential field calculations and the DEM measurements using EUV observations. We derived line of sight component of the coronal…

Solar and Stellar Astrophysics · Physics 2016-02-17 Shun Miyawaki , Kazumasa Iwai , Kiyoto Shibasaki , Daikou Shiota , Satoshi Nozawa

Observations of surface magnetic fields are now within reach for many stellar types thanks to the development of Zeeman-Doppler Imaging. These observations are extremely useful for constraining rotational evolution models of stars, as well…

Solar and Stellar Astrophysics · Physics 2015-09-24 Victor Réville , Allan Sacha Brun , Antoine Strugarek , Sean P. Matt , Jérôme Bouvier , Colin P. Folsom , Pascal Petit

A plethora of coronal models, from empirical to more complex magnetohydrodynamic (MHD) ones, are being used for reconstructing the coronal magnetic field topology and estimating the open magnetic flux. However, no individual solution fully…

A key question in understanding the observed magnetic field topologies of cool stars is the link between the small- and the large-scale magnetic field and the influence of the stellar parameters on the magnetic field topology. We examine…

Solar and Stellar Astrophysics · Physics 2018-05-23 L. T. Lehmann , M. M. Jardine , D. H. Mackay , A. A. Vidotto

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…

With the recent launch of the Hinode satellite our view of the nature and evolution of quiet-Sun regions has been improved. In light of the new high resolution observations, we revisit the study of the quiet Sun's topological nature.…

Astrophysics · Physics 2009-11-13 S. Regnier , C. E. Parnell , A. L. Haynes

This paper is the third in a series of papers working towards the construction of a realistic, evolving, non-linear force-free coronal field model for the solar magnetic carpet. Here, we present preliminary results of 3D time-dependent…

Solar and Stellar Astrophysics · Physics 2013-03-07 K. A. Meyer , D. H. Mackay , A. A. van Ballegooijen , C. E. Parnell

The theoretical concept that braided magnetic field lines in the solar corona may dissipate a sufficient amount of energy to account for the brightening observed in the active-region corona, has been substantiated by high-resolution…

Solar and Stellar Astrophysics · Physics 2015-06-17 J. K. Thalmann , S. K. Tiwari , T. Wiegelmann

Before using 3D MHD simulations of the solar photosphere in the determination of elemental abundances, one has to ensure that the correct amount of magnetic flux is present in the simulations. The presence of magnetic flux modifies the…

Solar and Stellar Astrophysics · Physics 2017-06-28 C. Beck , D. Fabbian , R. Rezaei , K. G. Puschmann

This article discusses the magnetic connectivity between the Sun and the Earth, which is essential for understanding solar wind and space weather events. Due to limited direct observations, reliable simulations are necessary. The most…

Solar and Stellar Astrophysics · Physics 2024-11-20 Silke Kennis , Barbara Perri , Stefaan Poedts

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