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Flows on the solar surface are linked to solar activity, and LCT is one of the standard techniques for capturing the dynamics of these processes by cross-correlating solar images. However, the link between contrast variations in successive…

Solar and Stellar Astrophysics · Physics 2015-06-16 M. Verma , M. Steffen , C. Denker

Context. Several upcoming and proposed space missions, such as Solar Orbiter, will be limited in telemetry and thus require data compression. Aims. We test the impact of data compression on local correlation tracking (LCT) of time-series of…

Solar and Stellar Astrophysics · Physics 2016-02-17 Björn Löptien , Aaron C. Birch , Tom L. Duvall , Laurent Gizon , Jesper Schou

We suggest a method that evaluates the horizontal velocity in the solar photosphere with easily observable values using a combination of neural network and radiative magnetohydrodynamics simulations. All three-component velocities of…

Solar and Stellar Astrophysics · Physics 2023-09-06 Hiroyuki Masaki , Hideyuki Hotta , Yukio Katsukawa , Ryohtaroh T. Ishikawa

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

Detailed knowledge of surface dynamics is one of the key points in understanding magnetic solar activity. The motions of the solar surface, to which we have direct access via the observations, tell us about the interaction between the…

Solar and Stellar Astrophysics · Physics 2023-03-15 T. Roudier , J. Ballot , J. M. Malherbe , M. Chane-Yook

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

Context: The interaction of plasma motions and magnetic fields is an important mechanism, which drives solar activity in all its facets. For example, photospheric flows are responsible for the advection of magnetic flux, the redistribution…

Solar and Stellar Astrophysics · Physics 2015-05-27 M. Verma , C. Denker

We apply time-distance helioseismology, local correlation tracking and Fourier spatial-temporal filtering methods to realistic supergranule scale simulations of solar convection and compare the results with high-resolution observations from…

We present a direct comparison between two different techniques time-distance helioseismology and a local correlation tracking method for measuring mass flows in the solar photosphere and in a near-surface layer: We applied both methods to…

Astrophysics · Physics 2009-11-13 Michal Svanda , Junwei Zhao , Alexander G. Kosovichev

Many helioseismic measurements suffer from substantial systematic errors. A particularly frustrating one is that time-distance measurements suffer from a large center to limb effect which looks very similar to the finite light travel time,…

Solar and Stellar Astrophysics · Physics 2015-06-11 Charles S. Baldner , Jesper Schou

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

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

Measuring the depth variation of the meridional flows is important for understanding the solar cycle, at least according to a number of dynamo models. While attempting to extend the early observations of \citet{giles_thesis} of…

Solar and Stellar Astrophysics · Physics 2012-08-27 Thomas L. Duvall, , Shravan M. Hanasoge

The determination of horizontal velocity fields at the solar surface is crucial to understanding the dynamics and magnetism of the convection zone of the sun. These measurements can be done by tracking granules. Tracking granules from…

Astrophysics · Physics 2009-11-13 R. Tkaczuk , M. Rieutord , N. Meunier , T. Roudier

Context: Supergranulation is a pattern of the velocity field at the surface of the Sun, which has been known about for more than fifty years, however, no satisfactory explanation of its origin has been proposed. Aims: New observational…

We present a detailed comparison between simulations and seeing-free observations that takes into account the crucial influence of instrumental image degradation. We use images of quiet Sun granulation taken in the blue, green and red…

Solar and Stellar Astrophysics · Physics 2015-05-13 Sven Wedemeyer-Böhm , Luc Rouppe van der Voort

Supergranulation is characterized by horizontally divergent flows with typical length scales of 32 Mm in the solar photosphere. Unlike granulation, the size of which is comparable to both the thickness of the radiative boundary layer and…

Solar and Stellar Astrophysics · Physics 2016-10-05 Jean-Francois Cossette , Mark Peter Rast

We employ time sequences of images observed with a G-band filter (4305{\AA}) by the Solar Optical Telescope (SOT) on board of Hinode spacecraft at different latitude along solar central me-ridian to study vorticity of granular flows in…

Solar and Stellar Astrophysics · Physics 2017-02-02 A. A. Pevtsov

Improving irradiance forecasting is critical to further increase the share of solar in the energy mix. On a short time scale, fish-eye cameras on the ground are used to capture cloud displacements causing the local variability of the…

Computer Vision and Pattern Recognition · Computer Science 2022-10-26 Quentin Paletta , Joan Lasenby

Local-box hydrodynamical model atmospheres provide statistical information about a star's emergent radiation field which allows one to predict the level of its granulation-related micro-variability. Space-based photometry is now…

Solar and Stellar Astrophysics · Physics 2015-05-13 H. -G. Ludwig , R. Samadi , M. Steffen , T. Appourchaux , F. Baudin , K. Belkacem , P. Boumier , M. -J. Goupil , E. Michel
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