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We study the evolution of magnetic fields in accretion flows around six different sink particles in a global star formation simulation. Using the adaptive mesh refinement capabilities of \ramses, the vicinity of the sinks is resolved with a…

Solar and Stellar Astrophysics · Physics 2017-11-01 Michael Kuffmeier , Farrukh Nauman

We report the results of a magneto-hydrodynamic (MHD) simulation of a convective dynamo in a model solar convective envelope driven by the solar radiative diffusive heat flux. The convective dynamo produces a large-scale mean magnetic field…

Solar and Stellar Astrophysics · Physics 2014-06-18 Yuhong Fan , Fang Fang

We simulate the dynamics and the evolution of quiet Sun magnetic elements to produce a probability density function of the field strengths associated with such elements. The dynamics of the magnetic field are simulated through a numerical…

Astrophysics · Physics 2009-11-13 F. Berrilli , D. Del Moro , B. Viticchie

Using high-resolution ring analysis (HRRA) we deduce subsurface flows within magnetic active regions and within quiet sun. With this procedure we are capable of measuring flows with a horizontal spatial resolution of 2 degrees in…

Solar and Stellar Astrophysics · Physics 2011-02-11 Bradley W. Hindman , Deborah A. Haber , Juri Toomre

Observations of quiet Sun from the Solar Optical Telescope/Spectro-Polarimeter (SOT/SP) aboard the Hinode spacecraft would reveal the magnetic characters of the solar photosphere. By making use of the deep mode observations of three quiet…

Astrophysics · Physics 2008-12-18 Chunlan Jin , Jingxiu Wang , Meng Zhao

We use images of high spatial and temporal resolution, obtained using both ground- and space-based instrumentation, to investigate the role magnetic field inclination angles play in the propagation characteristics of running penumbral waves…

Solar and Stellar Astrophysics · Physics 2015-06-17 D. B. Jess , V. E. Reznikova , T. Van Doorsselaere , P. H. Keys , D. H. Mackay

Solar magnetic fields comprise an 11-year activity cycle, represented by the number of sunspots. The maintenance of such a solar magnetic field can be attributed to fluid motion in the convection zone, i.e. a dynamo. This study conducts the…

Solar and Stellar Astrophysics · Physics 2022-08-24 Ryota Shimada , Hideyuki Hotta , Takaaki Yokoyama

The Sun is the only star where we can resolve the intricate magnetism that all convective stars harbor. Yet, more than 99% of its visible surface along the solar cycle (the so-called quiet Sun) is filled with a tangled, unresolved…

Solar and Stellar Astrophysics · Physics 2021-07-14 J. C. Trelles Arjona , M. J. Martínez González , B. Ruiz Cobo

One of the main theories for heating of the solar corona is based on the idea that solar convection shuffles and tangles magnetic field lines to make many small-scale current sheets that, via reconnection, heat coronal loops. Tiwari et al…

Solar and Stellar Astrophysics · Physics 2025-05-08 V. Aparna , Sanjiv K. Tiwari , Ronald L. Moore , Navdeep K. Panesar , Brian Welsch , Bart De Pontieu , Aimee Norton

(abridged) Context: The mechanisms that cause the formation of sunspots are still unclear. Aims: We study the self-organisation of initially uniform sub-equipartition magnetic fields by highly stratified turbulent convection. Methods: We…

Solar and Stellar Astrophysics · Physics 2016-04-06 P. J. Käpylä , A. Brandenburg , N. Kleeorin , M. J. Käpylä , I. Rogachevskii

Solar convection is visible as a net blueshift of absorption lines, which becomes apparent when observing quiet Sun granulation. This blueshift exhibits variations from the disc centre to the solar limb due to differing projection angles…

Solar and Stellar Astrophysics · Physics 2023-12-13 M. Ellwarth , B. Ehmann , S. Schäfer , A. Reiners

Context: Observations indicate that the `quiet' solar photosphere outside active regions contains considerable amounts of magnetic energy and magnetic flux, with mixed polarity on small scales. The origin of this flux is unclear. Aims: We…

Astrophysics · Physics 2009-11-13 A. Voegler , M. Schuessler

We investigate the fine structure of magnetic fields in the atmosphere of the quiet Sun. We use photospheric magnetic field measurements from {\sc Sunrise}/IMaX with unprecedented spatial resolution to extrapolate the photospheric magnetic…

We describe a new form of small-scale magnetic flux emergence in the quiet Sun. This process seems to take vertical magnetic fields from the solar interior to the photosphere, where they appear above granular convection cells. High-cadence…

Astrophysics · Physics 2009-11-13 D. Orozco Suarez , L. R. Bellot Rubio , J. C. del Toro Iniesta , S. Tsuneta

The Sun features on its surface typical flow patterns called the granulation, mesogranulation, and supergranulation. These patterns arise due to convective flows transporting energy from the interior of the Sun to its surface. In this paper…

Solar and Stellar Astrophysics · Physics 2019-02-20 J. I. Campos Rozo , D. Utz , S. Vargas Dominguez , A. Veronig , T. Van Doorsselaere

Hydrodynamic simulations of granular convection predict the existence of supersonic flows covering ~3-4% of the solar surface at any time, but these flows have not been detected unambigously as yet. Using data from the spectropolarimeter…

Solar and Stellar Astrophysics · Physics 2009-07-22 L. R. Bellot Rubio

Properties of transient horizontal magnetic fields (THMFs) in both plage and quiet Sun regions are obtained and compared. Spectro-polarimetric observations with the Solar Optical Telescope (SOT) on the Hinode satellite were carried out with…

Astrophysics · Physics 2009-11-13 Ryohko Ishikawa , Saku Tsuneta

Magneto-convection simulations with two scenarios have been performed: In one, horizontal magnetic field is advected into the computational domain by fluid entering at the bottom. In the other, an initially uniform vertical magnetic field…

Astrophysics · Physics 2010-11-11 Robert F. Stein , David Bercik , Aake Nordlund

Swirl-shaped flow structures have been observed throughout the solar atmosphere, in both emission and absorption, at different altitudes and locations, and are believed to be associated with magnetic structures. However, the distribution…

Solar and Stellar Astrophysics · Physics 2024-12-06 Quan Xie , Jiajia Liu , Chris J. Nelson , Robert Erdélyi , Yuming Wang

We obtain lower limits on the amplitude of convective velocities in the deep solar convection zone based only on the observed properties of the differential rotation and meridional circulation together with simple and robust dynamical…

Solar and Stellar Astrophysics · Physics 2015-06-05 Mark S. Miesch , Nicholas A. Featherstone , Matthias Rempel , Regner Trampedach