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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

We present a new method for helioseismic diagnostics of the three-dimensional structure of sound speed, magnetic fields and flow velocities in the convection zone by inversion of acoustic travel-time data. The data are measurements of the…

Solar and Stellar Astrophysics · Physics 2018-06-11 A. G. Kosovichev , T. L. Duvall

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

We compare measurements of horizontal flows on the surface of the Sun using helioseismic time--distance inversions and coherent structure tracking of solar granules. Tracking provides 2D horizontal flows on the solar surface, whereas the…

Solar and Stellar Astrophysics · Physics 2015-06-15 M. Svanda , Th. Roudier , M. Rieutord , R. Burston , L. Gizon

In the same way that seismologists study the interior of the earth from the waves generated by earthquakes, heliosismology is the science that is interested in the study of oscillatory waves inside the Sun. Temperature, chemical…

Solar and Stellar Astrophysics · Physics 2017-09-22 Massinissa Hadjara

Accurate and efficient environment representation is crucial for robotic applications such as motion planning, manipulation, and navigation. Signed distance functions (SDFs) have emerged as a powerful representation for encoding distance to…

Robotics · Computer Science 2026-04-01 Zhirui Dai , Tianxing Fan , Mani Amani , Jaemin Seo , Ki Myung Brian Lee , Hyondong Oh , Nikolay Atanasov

The consistency of time--distance inversions for horizontal components of the plasma flow on supergranular scales in the upper solar convection zone is checked by comparing the results derived using two k--\omega filtering procedures --…

Solar and Stellar Astrophysics · Physics 2015-06-16 Michal Svanda

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

I analyse the maps recording the travel-time shifts caused by averaged plasma anomalies under an "average supergranule", constructed by means of statistical averaging over 5582 individual supergranules with large divergence signals detected…

Solar and Stellar Astrophysics · Physics 2015-06-11 Michal Svanda

According to time-distance helioseismology, information about internal fluid motions is encoded in the travel times of solar waves. The inverse problem consists of inferring 3-D vector flows from a set of travel-time measurements. Here we…

Solar and Stellar Astrophysics · Physics 2015-05-27 M. Svanda , L. Gizon , S. M. Hanasoge , S. D. Ustyugov

Improving methods for determining the subsurface structure of sunspots from their seismic signature requires a better understanding of the interaction of waves with magnetic field concentrations. We aim to quantify the impact of changes in…

Solar and Stellar Astrophysics · Physics 2017-08-30 T. Felipe , D. C. Braun , A. C. Birch

Time-distance helioseismology provides information about vector flows in the near-surface layers of the Sun by measuring wave travel times between points on the solar surface. Specific spatial averages of travel times have been proposed for…

Solar and Stellar Astrophysics · Physics 2015-01-05 Jan Langfellner , Laurent Gizon , Aaron 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

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

A time-distance helioseismic technique, similar to the one used by Ilonidis et al (2011), is applied to two independent numerical models of subsurface sound-speed perturbations to determine the spatial resolution and accuracy of phase…

Solar and Stellar Astrophysics · Physics 2021-06-02 John T. Stefan , Alexander G. Kosovichev , Andrey M. Stejko

Helioseismology, the study of global solar oscillations, has proved to be an extremely powerful tool for the investigation of the internal structure and dynamics of the Sun. Studies of time changes in frequency observations of solar…

Solar and Stellar Astrophysics · Physics 2023-03-15 M. P. Di Mauro

A crucial feature not widely accounted for in local helioseismology is that surface magnetic regions actually open a window from the interior into the solar atmosphere, and that the seismic waves leak through this window, reflect high in…

Solar and Stellar Astrophysics · Physics 2015-06-24 H. Moradi , P. S. Cally , D. Przybylski , S. Shelyag

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…

Meridional circulation regulates the Sun's interior dynamics and magnetism. While it is well accepted that meridional flows are poleward at the Sun's surface, helioseismic observations have yet to provide a definitive answer for the depth…

Time-distance helioseismic measurements in surface- and deep-focus geometries for wave-paths that distinguish surface magnetic contributions from those due to deeper perturbations beneath a large sunspot are presented and analysed. Travel…

Astrophysics · Physics 2008-02-21 S. P. Rajaguru