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Mapping the large-scale subsurface plasma flow profile within the Sun has been attempted using various methods for several decades. One such flow in particular is the meridional circulation, for which numerous studies have been published.…

Solar and Stellar Astrophysics · Physics 2023-08-23 Aleczander Herczeg , Jason Jackiewicz

Solar oscillations consist of a rich spectrum of internal acoustic waves and surface gravity waves, stochastically excited by turbulent convection. They have been monitored almost continuously over the last ten years with high-precision…

Astrophysics · Physics 2010-11-26 L. Gizon

Using a 3D global solver of the linearized Euler equations, we model acoustic oscillations over background velocity flow fields of single-cell meridional circulation with deep and shallow return flows as well as double-cell meridional…

Solar and Stellar Astrophysics · Physics 2022-02-15 Andrey M. Stejko , Alexander G. Kosovichev , Valery V. Pipin

Time-distance helioseismology is a set of powerful tools to study features below the Sun's surface. Inverse methods are needed to interpret time-distance measurements, with many examples in the literature. However, techniques that utilize a…

Solar and Stellar Astrophysics · Physics 2020-10-14 Jason Jackiewicz

Solar internal rotation at high latitudes is poorly constrained by acoustic-mode helioseismology. Global inertial modes observed on the Sun are highly sensitive to solar differential rotation and may provide new diagnostics of rotation in…

Solar and Stellar Astrophysics · Physics 2026-05-20 Prithwitosh Dey , Laurent Gizon , Yuto Bekki

Supergranules are convection cells seen at the Sun's surface as a space filling pattern of horizontal flows. While typical supergranules have diameters of about 35 Mm, they exhibit a broad spectrum of sizes from ~10 Mm to ~100 Mm. Here we…

Solar and Stellar Astrophysics · Physics 2015-06-04 David H. Hathaway

We use helioseismic holography to study the association of shallow flows with solar flare activity in about 250 large sunspot groups observed between 2010 and 2014 with the Helioseismic and Magnetic Imager on the Solar Dynamics Observatory.…

Solar and Stellar Astrophysics · Physics 2016-03-16 D. C. Braun

Large-scale plasma flows in the Sun's convection zone likely play a major role in solar dynamics on decadal timescales. In particular, quantifying meridional motions is a critical ingredient for understanding the solar cycle and the…

Solar and Stellar Astrophysics · Physics 2015-06-19 Shukur Kholikov , Alexander Serebryanskiy , Jason Jackiewicz

We analyze a solar active region observed by the Hinode CaII H line using the time-distance helioseismology technique, and infer wave-speed perturbation structures and flow fields beneath the active region with a high spatial resolution.…

Solar and Stellar Astrophysics · Physics 2014-11-20 Junwei Zhao , Alexander G. Kosovichev , Takashi Sekii

We perform helioseismic holography to assess the noise in p-mode travel-time shifts which would form the basis of inferences of large-scale flows throughout the solar convection zone. We also derive the expected travel times from a…

Astrophysics · Physics 2009-11-13 D. C. Braun , A. C. Birch

Helioseismic holography is a useful method to detect active regions on the Sun's far side and improve space weather forecasts. We aim to improve helioseismic holography by using a clear formulation of the problem, an accurate forward solver…

Solar and Stellar Astrophysics · Physics 2023-01-18 Dan Yang , Laurent Gizon , Hélène Barucq

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

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

We study the sensitivity of wave travel times to steady and spatially homogeneous horizontal flows added to a realistic simulation of the solar convection performed by Robert F. Stein, Ake Nordlund, Dali Georgobiani, and David Benson. Three…

Solar and Stellar Astrophysics · Physics 2015-05-13 S. Couvidat , A. C. Birch

We present a 3-dimensional (3D) numerical solver of the linearized compressible Euler equations (GALE -- Global Acoustic Linearized Euler), used to model acoustic oscillations throughout the solar interior. The governing equations are…

Solar and Stellar Astrophysics · Physics 2021-03-01 Andrey M. Stejko , Alexander G. Kosovichev , Nagi N. Mansour

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

Supergranulation is one of the most visible length scales of solar convection and has been studied extensively by local helioseismology. We use synthetic data computed with the Seismic Propagation through Active Regions and Convection…

Solar and Stellar Astrophysics · Physics 2015-06-12 D. E. Dombroski , A. C. Birch , D. C. Braun , S. M. Hanasoge

The Helioseismic and Magnetic Imager onboard the Solar Dynamics Observatory (SDO/HMI) provides continuous full-disk observations of solar oscillations. We develop a data-analysis pipeline based on the time-distance helioseismology method to…

Solar and Stellar Astrophysics · Physics 2015-05-27 J. Zhao , S. Couvidat , R. S. Bogart , K. V. Parchevsky , A. C. Birch , T. L. Duvall , J. G. Beck , A. G. Kosovichev , P. H. Scherrer

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…

The dynamics of the solar core cannot be properly constrained through the analysis of acoustic oscillation modes. Gravity modes are necessary to understand the structure and dynamics of the deepest layers of the Sun. Through recent…

Astrophysics · Physics 2009-11-13 S. Mathur , A. Eff-Darwich , R. A. García , S. Turck-Chièze