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Related papers: Inversions for Average Supergranular Flows Using F…

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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 aim of this work is to give new observational constraints on solar surface flows by determining the horizontal scale dependence of the velocity and intensity fields, as represented by their power spectra, and to offer some theoretical…

Solar and Stellar Astrophysics · Physics 2015-05-14 M. Rieutord , T. Roudier , F. Rincon , J. -M. Malherbe , N. Meunier , T. Berger , Z. Frank

Emerging active regions are associated with convective flows on the spatial scale and lifetimes of supergranules. To understand how these flows are involved in the formation of active regions, we aim to identify where active regions emerge…

Solar and Stellar Astrophysics · Physics 2024-07-17 Hannah Schunker , William Roland-Batty , Aaron C. Birch , Douglas C. Braun , Robert H. Cameron , L. Gizon

Supergranulation is a fluid-dynamical phenomenon taking place in the solar photosphere, primarily detected in the form of a vigorous cellular flow pattern with a typical horizontal scale of approximately 30--35~megameters, a dynamical…

Solar and Stellar Astrophysics · Physics 2018-07-05 Francois Rincon , Michel Rieutord

Filaments/prominences are cold plasma (~ 10000 K) embedded in the solar corona, two orders of magnitude hotter. Filament plasma is structured by the magnetic field in thin elongated threads. Counter-streaming flows have been observed. The…

Solar and Stellar Astrophysics · Physics 2025-06-24 Garima Karki , Brigitte Schmieder , Pascal Demoulin , Pooja Devi , Ramesh Chandra , Reetika Joshi

We present an analysis comparing the bulk--flow measurements for six recent peculiar velocity surveys, namely, ENEAR, SFI, RFGC, SBF and the Mark III singles and group catalogs. We study whether the direction of the bulk--flow estimates are…

Astrophysics · Physics 2009-03-19 Devdeep Sarkar , Hume A. Feldman , Richard Watkins

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

Correction due to finite speed of light is among the most inconsistent ones in absolute gravimetry. Formulas reported by different authors yield corrections scattered up to 8 $\mu$Gal with no obvious reasons. The problem, though noted…

Instrumentation and Detectors · Physics 2015-03-17 V D Nagornyi , Y M Zanimonskiy , Y Y Zanimonskiy

Spectra of the cellular photospheric flows are determined from full-disk Doppler velocity observations acquired by the Helioseismic and Magnetic Imager (HMI) instrument on the Solar Dynamics Observatory (SDO) spacecraft. Three different…

Solar and Stellar Astrophysics · Physics 2015-10-01 David H. Hathaway , Thibaud Teil , Aimee A. Norton , Irina Kitiashvili

This Letter introduces unexpected diffusion properties in dense granular flows, and shows that they result from the development of partially jammed clusters of grains, or granular vortices. Transverse diffusion coefficients $D$ and average…

Soft Condensed Matter · Physics 2017-10-25 Prashidha Kharel , Pierre Rognon

Star-forming galaxies at high redshifts are the ideal targets to probe the hypothetical variation of the fine-structure constant alpha over cosmological time scales. We propose a modification of the alkali doublets method which allows us to…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-10 S. A. Levshakov , M. G. Kozlov

This paper reports turbulent boundary layer measurements made over open-cell reticulated foams with varying pore size and thickness, but constant porosity ($\epsilon \approx 0.97$). The foams were flush-mounted into a cutout on a flat…

Fluid Dynamics · Physics 2018-03-14 Christoph Efstathiou , Mitul Luhar

Solar supergranulation remains a mystery in spite of decades of intensive studies. Most of the papers about supergranulation deal with its surface properties. Local helioseismology provides an opportunity to look below the surface and see…

Solar and Stellar Astrophysics · Physics 2015-05-19 Radek Zlebcik , Michal Svanda , Mirek Klvana

We analyze the peculiar velocity field for 2400 flat spiral galaxies selected from an infrared sky survey (2MFGC). The distances to the galaxies have been determined from the Tully-Fisher relation in the photometric J band with a dispersion…

The radiofrequency (RF) transmit field is severely inhomogeneous at ultrahigh field due to both RF penetration and RF coil design issues. This particularly impairs image quality for sequences that use inversion pulses such as magnetization…

Computational Engineering, Finance, and Science · Computer Science 2010-07-05 Aaron C Hurley , Ali Al-Radaideh , Bai Li , Uwe Aickelin , Ron Coxon , Paul Glover , Penny A. Gowland

In preceding papers of this series, TF relations for galaxies in 24 clusters with radial velocities between 1000 and 9200 km/s (SCI sample) were obtained, a Tully-Fisher (TF) template relation was constructed and mean offsets of each…

Astrophysics · Physics 2009-10-30 R. Giovanelli , M. Haynes , J. Salzer , G. Wegner , L. da Costa , W. Freudling

We investigated the vertical penumbral plasma flow on small spatial scales using data recorded by the spectropolarimeter of the solar optical telescope onboard Hinode. To this end we computed maps of apparent Doppler velocities by comparing…

Solar and Stellar Astrophysics · Physics 2015-05-14 Morten Franz , Rolf Schlichenmaier

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

Measurements of the large cellular flows on the Sun were made by local correlation tracking of supergranules seen in full-disk Doppler images obtained by the HMI instrument on the NASA SDO satellite. The hourly measurements were averaged…

Solar and Stellar Astrophysics · Physics 2021-02-24 David H. Hathaway , Lisa A. Upton

Peculiar velocity surveys have non-uniform spatial distributions of tracers, so that the bulk flow estimated from them does not correspond to that of a simple volume such as a sphere. Thus bulk flow estimates are generally not strictly…

Astrophysics · Physics 2010-11-24 Richard Watkins , Hume A. Feldman , Michael J. Hudson