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We study the effect of localized sound-speed perturbations on global mode frequencies by applying techniques of global helioseismology on numerical simulations of the solar acoustic wave field. Extending the method of realization noise…

Astrophysics · Physics 2009-11-13 S. M. Hanasoge , T. P. Larson

The frequencies of the solar acoustic oscillations vary over the activity cycle. The variations in other activity proxies are found to be well correlated with the variations in the acoustic frequencies. However, each proxy has a slightly…

Solar and Stellar Astrophysics · Physics 2016-12-07 A. R. G. Santos , M. S. Cunha , P. P. Avelino , W. J. Chaplin , T. L. Campante

We analyse the spatial distribution of current helicity in solar active regions. A comparison of current helicity maps derived from three different instruments (Helioseismic and Magnetc Imager on board the Solar Dynamics Observatory,…

Solar and Stellar Astrophysics · Physics 2018-08-15 A. S. Kutsenko , V. I. Abramenko , K. M. Kuzanyan , Haiqing Xu , Hongqi Zhang

Active regions are open wounds in the Sun's surface. Seismic oscillations from the interior pass through them into the atmosphere, changing their nature in the process to fast and slow magneto-acoustic waves. The fast waves then partially…

Solar and Stellar Astrophysics · Physics 2013-09-12 Paul S. Cally , Hamed Moradi

One of the primary science objectives of Parker Solar Probe (PSP) is to determine the structures and dynamics of the plasma and magnetic fields at the sources of the solar wind. However, establishing the connection between {\it in situ}…

Since the Solar Dynamics Observatory (SDO) began recording ~ 1 TB of data per day, there has been an increased need to automatically extract features and events for further analysis. Here we compare the overall detection performance,…

Solar and Stellar Astrophysics · Physics 2011-09-05 Cis Verbeeck , Paul A. Higgins , Tufan Colak , Fraser T. Watson , Veronique Delouille , Benjamin Mampaey , Rami Qahwaji

We have studied solar cycle changes in the large frequency separations that can be observed in Birmingham Solar Oscillations Network (BiSON) data. The large frequency separation is often one of the first outputs from asteroseismic studies…

Solar and Stellar Astrophysics · Physics 2015-05-27 A. -M. Broomhall , W. J. Chaplin , Y. Elsworth , R. New

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

Computational heliophysics has shed light on the fundamental physical processes inside the Sun, such as the differential rotation, meridional circulation, and dynamo-generation of magnetic fields. However, despite the substantial advances,…

Solar and Stellar Astrophysics · Physics 2023-01-25 A. G. Kosovichev , G. Guerrero , A. M. Stejko , V. V. Pipin , A. V. Getling

Full-disk observations from missions such as the SDO and SOHO have enabled comprehensive studies of solar oscillations and dynamics. Interpreting helioseismic and photospheric data is complicated by systematic center-to-limb variations. To…

Solar and Stellar Astrophysics · Physics 2026-04-06 Irina N. Kitiashvili

The activity-related variations in the solar acoustic frequencies have been known for 30 years. However, the importance of the different contributions is still not well established. With this in mind, we developed an empirical model to…

Solar and Stellar Astrophysics · Physics 2017-11-08 A. R. G. Santos , M. S. Cunha , P. P. Avelino , W. J. Chaplin , T. L. Campante

Activity-related variations in the solar oscillation properties have been known for 30 years. However, the relative importance of the different contributions to the observed variations is not yet fully understood. Our goal is to estimate…

Solar and Stellar Astrophysics · Physics 2016-10-24 A. R. G. Santos , M. S. Cunha , P. P. Avelino , W. J. Chaplin , T. L. Campante

Global magnetic field models use as input synoptic data, which usually show "aging effects" as the longitudinal 360{\deg} information is not obtained simultaneously. Especially during times of increased solar activity, the evolution of the…

Solar and Stellar Astrophysics · Physics 2021-10-04 Stephan G. Heinemann , Manuela Temmer , Stefan J. Hofmeister , Aleksandar Stojakovic , Laurent Gizon , Dan Yang

Recent models of variations of the Sun's structure with the 11-year activity cycle by Sofia et al (2005) predict strong non-homologous changes of the radius of subsurface layers, due to subsurface magnetic fields and field-modulated…

Astrophysics · Physics 2009-11-13 S. Lefebvre , A. G. Kosovichev , J. P. Rozelot

One of the main obstacles in exoplanet detection when using the radial velocity (RV) technique is the presence of stellar activity signal induced by magnetic regions. In this context, a realistic simulated dataset that can provide…

Solar and Stellar Astrophysics · Physics 2025-01-29 Yinan Zhao , Xavier Dumusque , Michael Cretignier , Khaled Al Moulla , Momo Ellwarth , Ansgar Reiners , Alessandro Sozzetti

Context. Tracing wave activity from the photosphere to the corona has important implications for coronal heating and prediction of the solar wind. Despite extensive theory and simulations, the detection of waves in realistic MHD simulations…

Solar and Stellar Astrophysics · Physics 2025-08-28 George Cherry , Boris Gudiksen , Adam J. Finley

Intermittent magnetohydrodynamical turbulence is most likely at work in the magnetized solar atmosphere. As a result, an array of scaling and multi-scaling image-processing techniques can be used to measure the expected self-organization of…

Astrophysics · Physics 2007-05-23 Manolis K. Georgoulis

Solar wind back-mapping is a combination of ballistic mapping and magnetic mapping. By examining the different model ingredients that can affect the derived back-mapped position, we aim to provide a more precise estimate of the source…

Solar and Stellar Astrophysics · Physics 2025-02-12 Alexandros Koukras , Laurent Dolla , Rony Keppens

A new software (Soonspot) for the determination of the heliographic coordinates and areas of sunspots from solar images is presented. This program is very user-friendly and the accuracy of its results has been checked by using solar images…

Solar and Stellar Astrophysics · Physics 2021-03-19 P. Galaviz , V. M. S. Carrasco , F. Sánchez-Bajo , M. C. Gallego , J. M. Vaquero

Recent high-resolution observations of sunspot oscillations using simultaneously operated ground- and space-based telescopes reveal the intrinsic connection between different layers of the solar atmosphere. However, it is not clear whether…

Solar and Stellar Astrophysics · Physics 2015-10-13 S. Krishna Prasad , D. B. Jess , Elena Khomenko
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