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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

Intermediate Scattering Functions (ISF's) are measured for colloidal hard sphere systems using both Dynamic Light Scattering (DLS) and X-ray Photon Correlation Spectroscopy (XPCS). We compare the techniques, and discuss the advantages and…

Soft Condensed Matter · Physics 2015-05-19 V. A. Martinez , J. H. J Thijssen , F. Zontone , W. van Megen , G. Bryant

The methods for reducing the observations from the 150-foot Tower Telescope on Mt.~Wilson are reviewed and a new method for determining the North/South (sectoral) and the East/West (zonal) velocity components is described and applied. Due…

Solar and Stellar Astrophysics · Physics 2023-07-14 Roger K. Ulrich , Tham Tran , John Boyden

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

Current solar wind prediction is based on the Wang & Sheeley empirical relationship between the solar wind speed observed at 1 AU and the rate of magnetic flux tube expansion (FTE) between the photosphere and the inner corona, where FTE is…

Solar and Stellar Astrophysics · Physics 2020-10-21 Bala Poduval , Gordon Petrie , Luca Bertello

The solar photosphere provides us with a laboratory for understanding turbulence in a layer where the fundamental processes of transport vary rapidly and a strongly superadiabatic region lies very closely to a subadiabatic layer. Our tools…

Understanding solar flares is critical for predicting space weather, as their activity shapes how the Sun influences Earth and its environment. The development of reliable forecasting methodologies of these events depends on robust flare…

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

A 50 min time series of one-dimensional slit-spectrograms, taken in quiet sun at disk center, observed at the German Vacuum Tower Telescope (Observatorio del Teide), was used to study the global and spatial variations of different line…

Solar and Stellar Astrophysics · Physics 2013-03-14 K. G. Puschmann , M. Vazquez , J. A. Bonet , B. Ruiz Cobo , A. Hanslmeier

We investigate the ratio of the vertical and horizontal velocities of the photospheric plasma flows in the region of emerging magnetic fields on the Sun. We carried out a study of photospheric velocities during the first hours of the…

Solar and Stellar Astrophysics · Physics 2012-12-17 A. Khlystova

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

Magnetic fields (B-fields) are ubiquitous in the interstellar medium (ISM), and they play an essential role in the formation of molecular clouds and subsequent star formation. However, B-fields in interstellar environments remain…

Astrophysics of Galaxies · Physics 2024-10-18 Archana Soam , Ka Ho Yuen , Ian Stephens , Chi Yan Law , Ka Wai Ho , Simon Coudé

A two-dimensional velocity distribution in the UV-plane has been obtained for stars in the solar neighbourhood, using the Hipparcos astrometry for over 4000 survey stars with parallaxes greater than 10 mas and radial velocities found in the…

Astrophysics · Physics 2009-10-31 J. Skuljan , J. B. Hearnshaw , P. L. Cottrell

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

Horizontal atmospheric wind shear causes wind velocity fields to have different directions and speeds. In images of clouds acquired using ground-based sky imagers, clouds may be moving in different wind layers. To increase the performance…

Image and Video Processing · Electrical Eng. & Systems 2023-05-22 Guillermo Terrén-Serrano , Manel Martínez-Ramón

Modeling the mass distribution of galaxy-scale strong gravitational lenses is a task of increasing difficulty. The high-resolution and depth of imaging data now available render simple analytical forms ineffective at capturing lens…

Instrumentation and Methods for Astrophysics · Physics 2022-12-21 Aymeric Galan , Georgios Vernardos , Austin Peel , Frédéric Courbin , Jean-Luc Starck

Using turbulent MHD simulations (magnetic Reynolds numbers up to 8000) and Hinode observations, we study effects of turbulence on measuring the solar magnetic field outside active regions. Firstly, from synthetic Stokes V profiles for the…

Astrophysics · Physics 2011-02-11 Jonathan Pietarila Graham , Sanja Danilovic , Manfred Schuessler

The Polarimetric and Helioseismic Imager (SO/PHI) onboard Solar Orbiter is a spectropolarimeter scanning the Fe I line at 617.3 nm, providing data of the solar photosphere. The same line is sampled by the Helioseismic and Magnetic Imager…

Hyperspectral video (HSV) offers valuable spatial, spectral, and temporal information simultaneously, making it highly suitable for handling challenges such as background clutter and visual similarity in object tracking. However, existing…

Computer Vision and Pattern Recognition · Computer Science 2025-06-02 Hanzheng Wang , Wei Li , Xiang-Gen Xia , Qian Du , Jing Tian

Spectroscopic and spectropolarimetric observations, which rely on the Doppler effect, only provide access to the line-of-sight component of the solar plasma velocity (vz). However, many dynamic processes in the solar atmosphere involve…

Solar and Stellar Astrophysics · Physics 2026-03-30 H. Vila Crespo , J. M. Borrero , I. Milić , G. Vigeesh , A. Asensio Ramos
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