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A giant solar filament was visible on the solar surface from 2011 Nov. 8-23. The filament stretched over more than half a solar diameter. Multiwavelength data from the SDO instrument AIA (171, 193, 304, and 211\AA) were used to examine…

Solar and Stellar Astrophysics · Physics 2018-03-28 A. Diercke , C. Kuckein , M. Verma , C. Denker

We employ different shapes of apodizing windows in the local correlation tracking (LCT) routine to retrieve horizontal velocities using numerical simulations of convection. LCT was applied on a time sequence of temperature maps generated by…

Solar and Stellar Astrophysics · Physics 2015-06-23 Rohan E. Louis , B. Ravindra , Manolis K. Georgoulis , Manfred Küker

We compare measurements of horizontal flows on the surface of the Sun using helioseismic time--distance inversions and coherent structure tracking of solar granules. Tracking provides 2D horizontal flows on the solar surface, whereas the…

Solar and Stellar Astrophysics · Physics 2015-06-15 M. Svanda , Th. Roudier , M. Rieutord , R. Burston , L. Gizon

We study the structure and reveal the physical nature of the reversed granulation pattern in the solar photosphere by means of 3-dimensional radiative hydrodynamics simulations. We used the MURaM code to obtain a realistic model of the…

Astrophysics · Physics 2009-11-11 M. C. C. Cheung , M. Schuessler , F. Moreno-Insertis

Turbulent convection efficiently transports energy up to the solar photosphere, but its multi-scale nature and dynamic properties are still not fully understood. Several works in the literature have investigated the emergence of patterns of…

Solar and Stellar Astrophysics · Physics 2018-03-28 F. Giannattasio , F. Berrilli , G. Consolini , D. Del Moro , M. Gosic , L. Bellot Rubio

Imaging systematics refers to the inhomogeneous distribution of a galaxy sample caused by varying observing conditions and astrophysical foregrounds. Current mitigation methods correct the galaxy density fluctuations caused by imaging…

We compare horizontal velocities, vertical magnetic fields and evolution of trees of fragmenting granules (TFG, also named families of granules) derived in the quiet Sun at disk center from observations at solar minimum and maximum of the…

Solar and Stellar Astrophysics · Physics 2018-04-11 J. M. Malherbe , T. Roudier , R. Stein , Z. Frank

Context: Giant-cell convection is believed to be an important component of solar dynamics. For example, it is expected to play a crucial role in maintaining the Sun's differential rotation. Aims: We re-examine early reports of giant…

Solar and Stellar Astrophysics · Physics 2021-01-04 Chris S. Hanson , Thomas L. Duvall , Aaron C. Birch , Laurent Gizon , Katepalli R. Sreenivasan

The observed magnetic field on the solar surface is characterized by a very complex spatial and temporal behavior. Although feature-tracking algorithms have allowed us to deepen our understanding of this behavior, subjectivity plays an…

The meridional flow in the Sun is an axisymmetric flow that is generally poleward directed at the surface, and is presumed to be of fundamental importance in the generation and transport of magnetic fields. Its true shape and strength,…

Solar and Stellar Astrophysics · Physics 2015-06-11 Thomas Hartlep , Junwei Zhao , Alexander G. Kosovichev , Nagi N. Mansour

In the quiet regions on the solar surface, turbulent convective motions of granulation play an important role in creating small-scale magnetic structures, as well as in energy injection into the upper atmosphere. The turbulent nature of…

Solar and Stellar Astrophysics · Physics 2020-03-04 Ryohtaroh T. Ishikawa , Yukio Katsukawa , Takayoshi Oba , Motoki Nakata , Kenichi Nagaoka , Tatsuya Kobayashi

An in-depth analysis of variability has been carried out on the 2 GHz and 8 GHz light curves from the impressive database of the US Navy's extragalactic source monitoring program at the Green Bank Interferometer (GBI), complemented by UMRAO…

High Energy Astrophysical Phenomena · Physics 2025-02-05 Nicola Marchili , Gunther Witzel , Margo F. Aller

We show how magnetic observations of the Sun can be used in conjunction with an axisymmetric flux-transport solar dynamo model in order to estimate the large-scale meridional circulation throughout the convection zone. Our innovative…

Solar and Stellar Astrophysics · Physics 2017-10-06 Ching Pui Hung , Laurène Jouve , Allan Sacha Brun , Alexandre Fournier , Olivier Talagrand

Context. Accurate photometry with ground based solar telescopes requires characterization of straylight. Scattering in Earth's atmosphere and in the telescope optics are potentially significant sources of straylight, for which the point…

Solar and Stellar Astrophysics · Physics 2016-01-13 Mats G. Löfdahl

We study the influence of large-scale photospheric motions on the estabilization of an eruptive filament, observed on October 6, 7, and 8, 2004, as part of an international observing campaign (JOP 178). Large-scale horizontal flows were…

Context. In local helioseismology, the travel times of acoustic waves propagating in opposite directions along the same meridian inform us about horizontal flows in the north-south direction. The longitudinal averages of the north-south…

Solar and Stellar Astrophysics · Physics 2022-08-31 Paul-Louis Poulier , Zhi-Chao Liang , Damien Fournier , Laurent Gizon

A large fraction of cool, low-mass stars exhibit brightness fluctuations that arise from a combination of convective granulation, acoustic oscillations, magnetic activity, and stellar rotation. Much of the short-timescale variability takes…

Solar and Stellar Astrophysics · Physics 2015-06-18 Steven R. Cranmer , Fabienne A. Bastien , Keivan G. Stassun , Steven H. Saar

Context: The Sun has recently been predicted to be an extended source of gamma-ray emission, produced by inverse-Compton (IC) scattering of cosmic-ray (CR) electrons on the solar radiation field. The emission was predicted to be extended…

Astrophysics · Physics 2009-06-23 Elena Orlando , Andrew W. Strong

Regions of quiet Sun generally exhibit a complex distribution of small-scale magnetic field structures, which interact with the near-surface turbulent convective motions. Furthermore, it is probable that some of these magnetic fields are…

Solar and Stellar Astrophysics · Physics 2015-06-18 Paul J. Bushby , Benjamin Favier

Measurements of oscillation frequencies of the Sun and stars can provide important independent constraints on their internal structure and dynamics. Seismic models of these oscillations are used to connect structure and rotation of the star…

Solar and Stellar Astrophysics · Physics 2015-05-18 Jishnu Bhattacharya , Shravan. M. Hanasoge , H. M. Antia