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Gravity-driven thick granular flows are relevant to many industrial and geophysical processes. In particular, it is important to know and understand the particle velocity distributions as we get deeper into the flow from the free surface.…

Soft Condensed Matter · Physics 2015-12-15 Etien Martinez , Oscar Sotolongo-Costa , Alfo Jose Batista-Leyva , Ernesto Altshuler

We have carried out numerical simulation based on the equations of radiation magnetohydrodynamics to study the interaction of solar granules and small-scale magnetic fields in photospheric regions with various magnetic fluxes. Four…

Solar and Stellar Astrophysics · Physics 2010-11-09 I. N. Atroshchenko , V. A. Sheminova

We experimentally study the velocity scaling of granular convection which is a possible mechanism of the regolith migration on the surface of small asteroids. In order to evaluate the contribution of granular convection to the regolith…

Geophysics · Physics 2015-06-19 Tomoya M. Yamada , Hiroaki Katsuragi

We study the motions of small solids, ranging from micron-sized dust grains to 100-m objects, in the vicinity of a local density enhancement of an isothermal gaseous solar nebula. Being interested in possible application of the results to…

Astrophysics · Physics 2009-11-07 Nader Haghighipour , Alan P. Boss

Exploding granules on the solar surface play a major role in the dynamics of the outer part of the convection zone, especially in the diffusion of the magnetic field. We aim to develop an automated procedure able to investigate the location…

Solar and Stellar Astrophysics · Physics 2024-10-30 J. Ballot , T. Roudier

Supergranules are believed to be an evidence for large-scale subsurface convection. The vertical component of the supergranular flow field is very hard to measure, but it is considered only a few m/s in and below the photosphere. Here I…

Solar and Stellar Astrophysics · Physics 2013-01-10 Michal Svanda

Below the scale of supergranules we find that cellular flows are present in the solar photosphere at two distinct size scales, approximately 2 Mm and 4 Mm, with distinct characteristic times. Simultaneously present in the flow is a…

Astrophysics · Physics 2015-06-24 J. K. Lawrence , A. C. Cadavid , A. Ruzmaikin

Magneto-convection simulations on meso-granule and granule scales near the solar surface are used to study small scale dynamo activity, the emergence and disappearance of magnetic flux tubes, and the formation and evolution of micropores.…

Astrophysics · Physics 2007-05-23 Robert F. Stein , Aake Nordlund

Context: Studying the motions on the solar surface is fundamental for understanding how turbulent convection transports energy and how magnetic fields are distributed across the solar surface. Aims: From horizontal velocity measurements all…

Solar and Stellar Astrophysics · Physics 2015-06-22 Th. Roudier , M. Švanda , M. Rieutord , J. M. Malherbe , R. Burston , L. Gizon

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

Context. Local helioseismology has detected spatially extended converging surface flows into solar active regions. These play an important role in flux-transport models of the solar dynamo. Aims. We aim to validate the existence of the…

Solar and Stellar Astrophysics · Physics 2017-10-04 B. Löptien , A. C. Birch , T. L. Duvall , L. Gizon , B. Proxauf , J. Schou

We use subsurface-flow velocity maps inferred by time--distance helioseismology from Doppler measurements with the Helioseismic and Magnetic Imager (HMI) of the Solar Dynamics Observatory (SDO) to investigate variations of large-scale…

Solar and Stellar Astrophysics · Physics 2025-10-01 Alexander V. Getling , Alexander G. Kosovichev

The differential rotation of the sun, as deduced from helioseismology, exhibits a prominent radial shear layer near the top of the convection zone wherein negative radial gradients of angular velocity are evident in the low- and…

Astrophysics · Physics 2009-11-07 M. L. DeRosa , P. A. Gilman , J. Toomre

Galaxy clusters are currently the endpoint of the hierarchical structure formation; they form via the accretion of dark matter and cosmic gas from their local environment. In particular, filaments contribute grandly by accreting gas from…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-14 Théo Lebeau , Saleem Zaroubi , Nabila Aghanim , Jenny G. Sorce , Mathieu Langer

Recent observations revealed that small magnetic elements abundant at the solar surface move poleward with a velocity which seems to be lower than the plasma velocity $U_{\theta}$. Guerrero et al. (2011) explained this discrepancy as a…

Solar and Stellar Astrophysics · Physics 2015-06-03 G. Guerrero , M. Rheinhardt , M. Dikpati

Recent analysis revealed that supergranules (convection cells seen at the Sun's surface) are advected by the zonal flows at depths equal to the widths of the cells themselves. Here we probe the structure of the meridional circulation by…

Solar and Stellar Astrophysics · Physics 2015-06-11 David H. Hathaway

Recently, we have developed a method useful for mapping large-scale horizontal velocity fields in the solar photosphere. The method was developed, tuned and calibrated using the synthetic data. Now, we applied the method to the series of…

Astrophysics · Physics 2009-11-13 Michal Svanda , Mirek Klvana , Michal Sobotka , Vaclav Bumba

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

Tens of thousands of solar-like oscillating stars have been observed by space missions. Their photometric variability in the Fourier domain can be parameterized by a sum of two super-Lorentizian functions for granulation and a…

Solar and Stellar Astrophysics · Physics 2022-02-15 Zhao Guo , Eric B. Ford , Dennis Stello , Jacob K. Luhn , Suvrath Mahadevan , Arvind F. Gupta , Jie Yu

Velocity fields in the cosmic web are fundamental to structure formation but remain difficult to observe directly beyond the linear regime. Here we present observational evidence that galaxy filaments connecting pairs of galaxy clusters…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-27 Ji Yao , Huanyuan Shan , Pengjie Zhang , Xiaohu Yang , Jiale Zhou , Jiaxin Han , Peng Wang