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Time-distance helioseismology is one of the primary tools for studying the solar meridional circulation. However, travel-time measurements of the subsurface meridional flow suffer from a variety of systematic errors, such as a…

Solar and Stellar Astrophysics · Physics 2017-04-26 Zhi-Chao Liang , Aaron C. Birch , Thomas L. Duvall , Laurent Gizon , Jesper Schou

The solar interior is filled with turbulent thermal convection, which plays a key role in the energy and momentum transport and the generation of the magnetic field. The turbulent flows in the solar interior cannot be optically detected due…

Solar and Stellar Astrophysics · Physics 2024-10-10 Hiroyuki Masaki , Hideyuki Hotta

Context: Helioseismic inversions rely largely on sensitivity kernels, 3-D spatial functions describing how do the changes in the solar interior translate into the changes of helioseismic observables. These sensitivity kernels come in most…

Solar and Stellar Astrophysics · Physics 2024-09-25 Michal Svanda , Daniel Chmurny

Spectral analysis of the spatial structure of solar subphotospheric convection is carried out for subsurface flow maps constructed using the time--distance helioseismological technique. The source data are obtained from the Helioseismic and…

Solar and Stellar Astrophysics · Physics 2022-09-27 Alexander V. Getling , Alexander G. Kosovichev

An essential ingredient in kinematic dynamo models is the velocity field within the solar convection zone. In particular, the differential rotation is now well constrained by helioseismic observations. Helioseismology also gives us…

Astrophysics · Physics 2009-06-30 Andrés Muñoz-Jaramillo , Dibyendu Nandy , Petrus C. H. Martens

Context: The solar rotation profile is conical rather than cylindrical as one could expect from classical rotating fluid dynamics (e.g. Taylor-Proudman theorem). Thermal coupling to the tachocline, baroclinic effects and latitudinal…

Solar and Stellar Astrophysics · Physics 2015-05-14 A. S. Brun , H. M. Antia , K. Chitre

The meridional flow in the Sun is an axisymmetric flow that is generally poleward directed at the surface, and is presumed to be of fundamental importance in the generation and transport of magnetic fields. Its true shape and strength,…

Solar and Stellar Astrophysics · Physics 2015-06-11 Thomas Hartlep , Junwei Zhao , Alexander G. Kosovichev , Nagi N. Mansour

Our Sun, primarily composed of ionized hydrogen and helium, has a surface temperature of 5777~K and a radius $R_\odot \approx 696,000$ km. In the outer $R_\odot/3$, energy transport is accomplished primarily by convection. Using typical…

Solar and Stellar Astrophysics · Physics 2016-01-20 Shravan Hanasoge , Laurent Gizon , Katepalli R. Sreenivasan

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 perform a two-dimensional inversion of f-mode travel times to determine near-surface solar flows. The inversion is based on optimally localized averaging of travel times. We use finite-wavelength travel-time sensitivity functions and a…

Astrophysics · Physics 2009-11-13 J. Jackiewicz , L. Gizon , A. C. Birch , M. J. Thompson

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

The Sun supports a rich spectrum of internal waves that are continuously excited by turbulent convection. The GONG network and the MDI/SOHO space instrument provide an exceptional data base of spatially-resolved observations of solar…

Solar and Stellar Astrophysics · Physics 2015-05-14 L. Gizon , A. C. Birch , H. C. Spruit

Global hydrodynamic simulations of internal solar dynamics have focused on replicating the conditions for solar-like differential rotation and meridional circulation using the results of helioseismic inversions as a constraint. Inferences…

We derive expectations for signatures in the measured travel times of waves that interact with thermal anomalies and jets. A series of numerical experiments that involve the dynamic linear evolution of an acoustic wave field in a solar-like…

Astrophysics · Physics 2011-02-11 Shravan M. Hanasoge , Thomas L. Duvall

Helioseismic observations have provided valuable datasets with which to pursue the detailed investigation of solar interior dynamics. Among various methods to analyse these data, normal-mode coupling has proven to be a powerful tool, used…

Solar and Stellar Astrophysics · Physics 2021-10-20 Prasad Mani , Shravan Hanasoge

Helioseismic signatures of dynamo waves have recently been discovered in variations of the solar differential rotation, offering valuable insights into the type of dynamo mechanism operating in the solar convection zone. To characterize…

Solar and Stellar Astrophysics · Physics 2025-05-19 Krishnendu Mandal , Alexander G. Kosovichev , Valery V. Pipin , Sylvain G. Korzennik

Helioseismic inversions reveal a major discrepancy in sound speed between the Sun and the standard solar model just below the base of solar convection zone. We demonstrate that this discrepancy is caused by the inherent shortcomings of the…

Solar and Stellar Astrophysics · Physics 2012-10-17 Chunguang Zhang , Licai Deng , Darun Xiong , Jørgen Christensen-Dalsgaard

The solar atmosphere is extremely dynamic, and many important phenomena develop on small scales that are unresolved in observations with the Helioseismic and Magnetic Imager (HMI) instrument on the Solar Dynamics Observatory (SDO). For…

Solar and Stellar Astrophysics · Physics 2015-08-06 Irina N. Kitiashvili , Sebastien Couvidat , Andreas Lagg

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

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