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As large--distance rays (say, 10\,-\,$24 ^\circ$) approach the solar surface approximately vertically, travel times measured from surface pairs for these large separations are mostly sensitive to vertical flows, at least for shallow flows…

Solar and Stellar Astrophysics · Physics 2015-06-05 Thomas L. Duvall, , Shravan M. Hanasoge

Flow vorticity is a fundamental property of turbulent convection in rotating systems. Solar supergranules exhibit a preferred sense of rotation, which depends on the hemisphere. This is due to the Coriolis force acting on the diverging…

Solar and Stellar Astrophysics · Physics 2015-09-09 J. Langfellner , L. Gizon , A. C. Birch

We report the discovery and characterization of high-speed (>100 km/s) horizontal flows in solar active regions, making use of the Sun-as-a-star spectroscopy in the range 5-105 nm provided by the EVE (Extreme Ultraviolet Variability…

Collective cell flows are a hallmark of tissue dynamics in development, wound healing, and various diseases. Here, we perform experiments on epithelial MDCK cell monolayers, over tens of hours without jamming, on millimeter-scale…

Tissues and Organs · Quantitative Biology 2025-11-27 Guillaume Duprez , Mélina Durande , François Graner , Hélène Delanoë-Ayari

We used the time correlation of shadowgraph images to determine the angle $\Theta$ of the horizontal component of the plume velocity above (below) the center of the bottom (top) plate of a cylindrical Rayleigh-B\'enard cell of aspect ratio…

Chaotic Dynamics · Physics 2009-11-10 Denis Funfschilling , Guenter Ahlers

The angular width of Earth's Hadley cell has been related to the square root of the product of the tropospheric thickness and the buoyancy frequency, and to the inverse of the square root of the angular velocity and the planetary radius.…

Earth and Planetary Astrophysics · Physics 2019-07-24 Karlie N. Rees , Timothy J. Garrett

Large-scale velocity fields in the solar photosphere remain a mystery in spite of many years of intensive studies. In this thesis, the new method of the measurements of the solar photospheric flow fields is proposed. It is based on local…

Astrophysics · Physics 2007-12-13 Michal Svanda

Photospheric vortex flows are thought to play a key role in the evolution of magnetic fields. Recent studies show that these swirling motions are ubiquitous in the solar surface convection and occur in a wide range of temporal and spatial…

Solar and Stellar Astrophysics · Physics 2018-03-07 Iker S. Requerey , Basilio Ruiz Cobo , Milan Gošić , Luis R. Bellot Rubio

Supergranules are convection cells seen at the Sun's surface as a space filling pattern of horizontal flows. While typical supergranules have diameters of about 35 Mm, they exhibit a broad spectrum of sizes from ~10 Mm to ~100 Mm. Here we…

Solar and Stellar Astrophysics · Physics 2015-06-04 David H. Hathaway

We present in this paper an exceptional scientific dataset allowing to investigate the structure and evolution of the interior of solar supergranulation cells. Trees of Fragmenting Granules (TFG) and associated flows were evidenced using…

Solar and Stellar Astrophysics · Physics 2025-03-13 Jean-Marie Malherbe , Thierry Roudier

The eddy viscosity in the solar supergranulation layer is derived from the observed rotational shear by computing theoretical rotation laws for the outermost parts of the solar convection zone using the results from numerical simulations of…

Astrophysics · Physics 2016-08-16 G. Rüdiger , M. Küker

Context: The determination of the underlying mechanisms of the magnetic elements diffusion over the solar surface is still a challenge. Understanding the formation and evolution of the solar network (NE) is a challenge, because it provides…

Solar and Stellar Astrophysics · Physics 2016-06-08 Th. Roudier , J. M. Malherbe , M. Rieutord , Z. Frank

Supergranules create a peak in the spatial spectrum of photospheric velocity features. They have some properties of convection cells but their origin is still being debated in the literature. The time-distance helioseismology constitutes a…

Solar and Stellar Astrophysics · Physics 2021-02-24 David Korda , Michal Švanda

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

Supergranulation on the surface of the Sun is an organized cellular flow pattern with a characteristic scale of 30 Mm. It is superficially similar to the well understood granulation that operates at the 1.5 Mm natural scale of convection,…

Astrophysics · Physics 2009-11-07 L. Gizon , T. L. Duvall , J. Schou

The complex spatiotemporal flow patterns in living tissues, driven by active forces, have many of the characteristics associated with inertial turbulence even though the Reynolds number is extremely low. Analyses of experimental data from…

Soft Condensed Matter · Physics 2022-11-29 Xin Li , Sumit Sinha , T. R. Kirkpatrick , D. Thirumalai

Aims: The interactions of velocity scales on the Sun's surface, from granulation to supergranulation are still not understood, nor are their interaction with magnetic fields. We thus aim at giving a better description of dynamics in the…

Solar and Stellar Astrophysics · Physics 2009-02-16 T. Roudier , M. Rieutord , D. Brito , F. Rincon , J. M. Malherbe , N. Meunier , T. Berger , Z. Frank

We model the solar horizontal velocity power spectrum at scales larger than granulation using a two-component approximation to the mass continuity equation. The model takes four times the density scale height as the integral (driving) scale…

Solar and Stellar Astrophysics · Physics 2015-06-22 J. W. Lord , R. H. Cameron , M. P. Rast , M. Rempel , 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

Atmospheric flows exhibit long-range spatiotemporal correlations manifested as the fractal geometry to the global cloud cover pattern concomitant with inverse power-law form for power spectra of temporal fluctuations of all scales ranging…

General Physics · Physics 2007-05-23 A. M. Selvam , S. Fadnavis