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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

A major goal of helioseismology is the three-dimensional reconstruction of the three velocity components of convective flows in the solar interior from sets of wave travel-time measurements. For small amplitude flows, the forward problem is…

Numerical Analysis · Mathematics 2017-03-28 D. Fournier , L. Gizon , M. Holzke , T. Hohage

Local helioseismology provides a unique opportunity to investigate the subsurface structure and dynamics of active regions and their effect on the large-scale flows and global circulation of the Sun. We use measurements of plasma flows in…

Solar and Stellar Astrophysics · Physics 2016-07-19 Alexander G. Kosovichev , Junwei Zhao , Stathis Ilonidis

Accurate determination of the rotation rate in the radiative zone of the sun from helioseismic observations requires rotational frequency splittings of exceptional quality as well as reliable inversion techniques. We present here inferences…

Astrophysics · Physics 2009-11-13 A. Eff-Darwich , S. G. Korzennik , S. J. Jimenez-Reyes , R. A. Garcia

Local helioseismology provides unique information about the subsurface structure and dynamics of sunspots and active regions. However, because of complexity of sunspot regions local helioseismology diagnostics require careful analysis of…

In stars and planets natural processes heat convective flows in the bulk of a convective region rather than at hard boundaries. By characterizing how convective dynamics are determined by the strength of an internal heating source we can…

Fluid Dynamics · Physics 2024-04-16 Whitney T. Powers , Evan H. Anders , Benjamin P. Brown

Meridional circulation is a crucial component of the Sun's internal dynamics, but its inference in the deep interior is complicated by a systematic center-to-limb effect in helioseismic measurement techniques. Previously, an empirical…

Solar and Stellar Astrophysics · Physics 2017-11-15 Ruizhu Chen , Junwei Zhao

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

The 3D structure of solar wind and its evolution in time is needed for heliospheric modeling and interpretation of energetic neutral atoms observations. We present a model to retrieve the solar wind structure in heliolatitude and time using…

Solar and Stellar Astrophysics · Physics 2015-06-03 J. M. Sokol , M. Bzowski , M. Tokumaru , K. Fujiki , D. J. McComas

We use a publicly available numerical wave-propagation simulation of Hartlep et al. 2011 to test the ability of helioseismic holography to detect signatures of a compact, fully submerged, 5% sound-speed perturbation placed at a depth of 50…

Solar and Stellar Astrophysics · Physics 2015-06-11 Douglas C. Braun

The interpretation of helioseismic measurements, such as wave travel-time, is based on the computation of kernels that give the sensitivity of the measurements to localized changes in the solar interior. These are computed using the ray or…

Solar and Stellar Astrophysics · Physics 2018-09-12 Damien Fournier , Chris S. Hanson , Laurent Gizon , Helene Barucq

Recent hydrodynamical simulations of convection in a solar-like model suggest that penetrative convective flows at the boundary of the convective envelope modify the thermal background in the overshooting layer. Based on these results, we…

Solar and Stellar Astrophysics · Physics 2022-03-14 Baraffe I , Constantino T , Clarke J , Le Saux A , Goffrey T , Guillet T , Pratt J , Vlaykov D. G

We describe a 3D finite-difference spherical anelastic MHD (FSAM) code for modeling the subsonic dynamic processes in the solar convective envelope. A comparison of this code with the widely used global spectral anlastic MHD code, ASH…

Solar and Stellar Astrophysics · Physics 2013-05-29 Yuhong Fan , Nicholas Featherstone , Fang Fang

Context. Tracing wave activity from the photosphere to the corona has important implications for coronal heating and prediction of the solar wind. Despite extensive theory and simulations, the detection of waves in realistic MHD simulations…

Solar and Stellar Astrophysics · Physics 2025-08-28 George Cherry , Boris Gudiksen , Adam J. Finley

Normal modes are coupled by the presence of perturbations in the Sun, providing a novel and under-appreciated helioseismic technique with which to image the solar interior. The process of measuring coupling between normal modes is…

Solar and Stellar Astrophysics · Physics 2018-07-18 Shravan Hanasoge

We have carried out inversions of travel times as measured by Gizon et al. (2020) to infer the internal profile of the solar meridional circulation (MC). A linear inverse problem has been solved by the regularized least-squares method with…

Solar and Stellar Astrophysics · Physics 2024-06-19 Yoshiki Hatta , Hideyuki Hotta , Takashi Sekii

We explore the general properties of near-surface flows around solar active regions. Helioseismic holography is applied to HMI Dopplergrams yielding nearly 5000 flow measurements of 336 unique active regions observed by the Solar Dynamics…

Solar and Stellar Astrophysics · Physics 2019-03-20 D. C. Braun

We show how magnetic observations of the Sun can be used in conjunction with an axisymmetric flux-transport solar dynamo model in order to estimate the large-scale meridional circulation throughout the convection zone. Our innovative…

Solar and Stellar Astrophysics · Physics 2017-10-06 Ching Pui Hung , Laurène Jouve , Allan Sacha Brun , Alexandre Fournier , Olivier Talagrand

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

The measurement of the Sun's surface motions with a high spatial and temporal resolution is still a challenge. We wish to validate horizontal velocity measurements all over the visible disk of the Sun from Solar Dynamics Observatory/…

Solar and Stellar Astrophysics · Physics 2015-06-15 Th. Roudier , M. Rieutord , V. Prat , J. M. Malherbe , N. Renon , Z. Frank , M. Svanda , T. Berger , R. Burston , L. Gizon