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We present a method to determine the complex coupling parameter of a two-coupled-modes system by directly measuring the coupled eigenmodes rather than their eigenvalues. This method is useful because mode-mixing can be observed even if…

Optics · Physics 2022-01-19 C. Koks , M. P. van Exter

Element settling inside the Sun now becomes detectable from the comparison of the observed oscillation modes with the results of the theoretical models. This settling is due, not only to gravitation, but also to thermal diffusion and…

Astrophysics · Physics 2009-10-30 Sylvie Vauclair

Being able to image active regions on the Sun's far side is useful for modeling the global-scale magnetic field around the Sun, and for predicting the arrival of major active regions that rotate around the limb onto the near side.…

Solar and Stellar Astrophysics · Physics 2020-01-08 Junwei Zhao , Dominick Hing , Ruizhu Chen , Shea Hess Webber

The Sun's axisymmetric flows, differential rotation and meridional flow, govern the dynamics of the solar magnetic cycle and variety of methods are used to measure these flows, each with its own strengths and weaknesses. Flow measurements…

Solar and Stellar Astrophysics · Physics 2021-09-08 Sushant S. Mahajan , David H. Hathaway , Andrés Muñoz-Jaramillo , Petrus C. Martens

The continuous high spatial-resolution Doppler observation of the Sun by Solar Dynamics Observatory / Helioseismic and Magnetic Imager allows us to compute helioseismic k-omega power-spectrum diagram using only oscillations inside a…

Solar and Stellar Astrophysics · Physics 2015-06-11 Junwei Zhao , Dean-Yi Chou

The analysis of waves in the visible side of the Sun allows the detection of active regions in the farside through local helioseismology techniques. The knowledge of the magnetism in the whole Sun, including the non-visible hemisphere, is…

Solar and Stellar Astrophysics · Physics 2019-12-04 T. Felipe , A. Asensio Ramos

We perform a quantitative analysis of the solar composition problem by using a statistical approach that allows us to combine the information provided by helioseimic and solar neutrino data in an effective way. We include in our analysis…

Solar and Stellar Astrophysics · Physics 2015-06-18 F. L. Villante , A. M. Serenelli , F. Delahaye , M. H. Pinsonneault

Helioseismology has taught us a great deal about the stratification and kinematics of the solar interior, sufficient for us to embark upon dynamical studies more detailed than have been possible before. The most sophisticated studies to…

Solar and Stellar Astrophysics · Physics 2015-06-02 D. O. Gough

It is well known that the observed amplitude of solar oscillations is lower in sunspots than in quiet regions of the Sun. We show that this local reduction in oscillation amplitudes combined with the phase-speed filtering procedure in…

Astrophysics · Physics 2009-11-11 S. P. Rajaguru , A. C. Birch , T. L. Duvall , M. J. Thompson , J. Zhao

In helioseismology, there is a well-known offset between observed and computed oscillation frequencies. This offset is known to arise from improper modeling of the near-surface layers of the Sun, and a similar effect must occur for models…

Astrophysics · Physics 2009-11-13 Hans Kjeldsen , Timothy R. Bedding , Joergen Christensen-Dalsgaard

Departures from standard spherically symmetric solar models, in the form of perturbations such as global and local-scale flows and structural asphericities, result in the splitting of eigenfrequencies in the observed spectrum of solar…

Solar and Stellar Astrophysics · Physics 2020-07-03 Srijan Bharati Das , Tuneer Chakraborty , Shravan M. Hanasoge , Jeroen Tromp

The experimental uncertainties in G between different experiments have important implications for helioseismology. We show that these uncertainties for the standard solar model lead to a range in the value of the square of the sound speed…

Astrophysics · Physics 2009-09-25 Ilidio Lopes , Joseph Silk

Time-distance helioseismology is the method of the study of the propagation of waves through the solar interior via the travel times of those waves. The travel times of wave packets contain information about the conditions in the interior…

Solar and Stellar Astrophysics · Physics 2019-02-20 David Korda , Michal Švanda

The questions whether the Sun shrinks with the solar activity and what causes this have been a subject of debate. Helioseismology provides means to measure with high precision the radial displacement of subsurface layers, co-called "seismic…

Solar and Stellar Astrophysics · Physics 2018-07-25 Alexander Kosovichev , Jean-Pierre Rozelot

Context. In time-distance helioseismology, wave travel times are measured from the two-point cross-covariance function of solar oscillations and are used to image the solar convection zone in three dimensions. There is, however, also…

Solar and Stellar Astrophysics · Physics 2017-03-08 Kaori Nagashima , Damien Fournier , Aaron C. Birch , Laurent Gizon

We review recent advances concerning helioseismology, solar models and solar neutrinos. Particularly we shall address the following points: i) helioseismic tests of recent SSMs; ii)the accuracy of the helioseismic determination of the sound…

Astrophysics · Physics 2014-10-13 G. Fiorentini , B. Ricci

Understanding and monitoring solar active regions is essential for operational space-weather forecasting and improved solar dynamo modeling. This requires comprehensive 360-degree observations of the Sun. While space-weather forecasting has…

Solar and Stellar Astrophysics · Physics 2026-03-04 Amr Hamada , Kiran Jain , Hanna Strecker , Charles Lindsey , David Orozco Suarez

Measuring the Sun's internal meridional flow is one of the key issues of helioseismology. Using the Fourier-Legendre analysis is a technique for addressing this problem. We validate this technique with the help of artificial helioseismic…

Solar and Stellar Astrophysics · Physics 2016-08-10 Markus Roth , Hans-Peter Doerr , Thomas Hartlep

The stratification near the base of the Sun's convective envelope is governed by processes of convective overshooting and element diffusion, and the region is widely believed to play a key role in the solar dynamo. The stratification in…

Solar and Stellar Astrophysics · Physics 2015-05-27 Joergen Christensen-Dalsgaard , Mario J. P. F. G. Monteiro , Matthias Rempel , Michael J. Thompson