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Related papers: Validating Time-Distance Helioseismology With Real…

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Realistic ab-initio 3D, radiative-hydrodynamical convection simulations of the solar granulation have been applied to FeI and FeII line formation. In contrast to classical analyses based on hydrostatic 1D model atmospheres the procedure…

Astrophysics · Physics 2007-05-23 M. Asplund , AA. Nordlund , R. Trampedach , C. Allende Prieto , R. F. Stein

Seismic surface wave tomography uses surface wave information to obtain velocity structures in the subsurface. Due to data noise and nonlinearity of the problem, surface wave tomography often has non-unique solutions. It is therefore…

Geophysics · Physics 2025-11-06 Wenda Yang , Xin Zhang

This study extends the flow measurement method initially proposed in [22] to three-dimensional scenarios, addressing the growing need for accurate and efficient non-contact flow measurement techniques in complex hydrodynamic environments.…

Numerical Analysis · Mathematics 2025-03-18 Jiwei Li , Lingyun Qiu , Zhongjing Wang , Hui Yu

Using solar-cycle long helioseismic measurements of meridional and zonal flows in the near-surface shear layer (NSSL) of the Sun, we study their spatio-temporal variations and connections to active regions. We find that near-surface inflows…

Solar and Stellar Astrophysics · Physics 2025-12-16 Anisha Sen , S. P. Rajaguru , Abhinav Govindan Iyer , Ruizhu Chen , Junwei Zhao , Shukur Kholikov

Accurately estimating latent velocity vector fields of atmospheric winds is crucial for understanding weather phenomena. Direct measurement of atmospheric winds is costly, especially in the upper atmosphere, so researchers attempt to…

Applications · Statistics 2025-06-12 Youssef Fahmy , Maria Laura Battagliola , Joseph Guinness

Solar differential rotation exhibits a prominent feature: its cyclic variations over the solar cycle, referred to as zonal flows or torsional oscillations, are observed throughout the convection zone. Given the challenge of measuring…

Solar and Stellar Astrophysics · Physics 2024-02-27 Krishnendu Mandal , Alexander G. Kosovichev , Valery V. Pipin

The estimation and analysis of large-scale bulk flow moments of peculiar velocity surveys is complicated by non-spherical survey geometry, the non-uniform sampling of the matter velocity field by the survey objects and the typically large…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-28 Shankar Agarwal , Hume A. Feldman , Richard Watkins

In this article, we derive and compute the sensitivity of measurements of coupling between normal modes of oscillation in the Sun to underlying flows. The theory is based on first-Born perturbation theory, and the analysis is carried out…

Solar and Stellar Astrophysics · Physics 2017-07-19 Shravan M. Hanasoge , Martin Woodard , H. M. Antia , Laurent Gizon , Katepalli R. Sreenivasan

Near-surface flows measured by the ring-diagram technique of local helioseismology show structures that persist over multiple rotations. We examine these phenomena using data from the {\em Global Oscillation Network Group} (GONG) and the…

Solar and Stellar Astrophysics · Physics 2015-08-19 R. Howe , R. W. Komm , D. Baker , L. Harra , L. van Driel-Gesztelyi , R. S. Bogart

Computer simulators are often used as a substitute of complex real-life phenomena which are either expensive or infeasible to experiment with. This paper focuses on how to efficiently solve the inverse problem for an expensive to evaluate…

Methodology · Statistics 2022-11-03 Pritam Ranjan , Joseph Resch , Abhyuday Mandal

Using a high cadence imaging spectropolarimetric observation of a sunspot and its surroundings in magnetically sensitive (FeI 6173 A) and insensitive (FeI 7090 A) upper photospheric absorption lines, we map the instantaneous wave phases and…

Solar and Stellar Astrophysics · Physics 2010-09-14 S. P. Rajaguru , R. Wachter , K. Sankarasubramanian , S. Couvidat

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

Solar subsurface zonal and meridional-flow profiles during the rising phase of solar cycle 24 are studied using time-distance helioseismology technique. The faster zonal bands in the torsional-oscillation pattern show strong hemispheric…

Solar and Stellar Astrophysics · Physics 2015-06-19 Junwei Zhao , A. G. Kosovichev , R. S. Bogart

Marine heat flow data, obtained with a Lister-type probe, consists of two temperature decay curves, frictional and heat pulse decay. Both follow the same physical model of a cooling cylinder. The mathematical model describing the decays is…

Geophysics · Physics 2022-01-19 Andreas Hartmann , Heinrich Villinger

In sequel to Moradi et al. [2009, ApJ, 690, L72], we employ two established numerical forward models (a 3D ideal MHD solver and MHD ray theory) in conjunction with time-distance helioseismology to probe the lateral extent of wave-speed…

Solar and Stellar Astrophysics · Physics 2011-01-04 H. Moradi , S. M. Hanasoge

Today's picture of the internal solar rotation rate profile results essentially from helioseismic analyses of frequency splittings of resonant acoustic waves. Here we present another, complementary estimation of the internal solar rotation…

Solar and Stellar Astrophysics · Physics 2020-02-17 Ariane Schad , Markus Roth

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 analyze spectral properties of solar convection in the range of depths from 0 to 19~Mm using subsurface flow maps obtained by the time-distance heiioseismology analysis of solar-oscillation data from the Helioseismic and Magnetic Imager…

Solar and Stellar Astrophysics · Physics 2022-03-01 Alexander V. Getling , Alexander G. Kosovichev

Using Doppler velocity data from the SOI/MDI instrument onboard the SoHO spacecraft, we do time-distance helioseismic inversions for sound-speed perturbations beneath 16 sunspots observed in high-resolution mode. We clearly detect ring-like…

Astrophysics · Physics 2011-02-11 S. Couvidat , S. P. Rajaguru

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
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