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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

Time-lapse images carry out important information about dynamic changes in Earth's interior which can be inferred using different Full Waveform Inversion (FWI) schemes. The estimation process is performed by manipulating more than one…

Supergranules are divergent 30-Mm sized cellular flows observed everywhere at the solar photosphere. Their place in the hierarchy of convective structures and their origin remain poorly understood (Rincon et al., 2018). Estimating…

Solar and Stellar Astrophysics · Physics 2019-10-09 Vedant Dhruv , Jishnu Bhattacharya , Shravan Hanasoge

Local helioseismology has opened new frontiers in our quest for understanding of the internal dynamics and dynamo on the Sun. Local helioseismology reconstructs subsurface structures and flows by extracting coherent signals of acoustic…

Solar and Stellar Astrophysics · Physics 2016-07-20 Alexander G. Kosovichev , Junwei Zhao

Helioseismology is one of the most successful fields of astrophysics. The observation and characterization of solar oscillation has allowed solar seismologists to study the internal structure and dynamics of the Sun with unprecedented…

Solar and Stellar Astrophysics · Physics 2019-12-05 G. Buldgen

A common task in experimental sciences is to fit mathematical models to real-world measurements to improve understanding of natural phenomenon (reverse-engineering or inverse modeling). When complex dynamical systems are considered, such as…

Numerical Analysis · Mathematics 2018-06-18 Jean-Charles Croix , Nicolas Durrande , Mauricio Alvarez

A strategy is presented to incorporate prior information from conceptual geological models in probabilistic inversion of geophysical data. The conceptual geological models are represented by multiple-point statistics training images (TIs)…

Geophysics · Physics 2017-01-06 T. Lochbühler , J. A. Vrugt , M. Sadegh , N. Linde

Standard maximum-likelihood estimators for binary-star and exoplanet eccentricities are biased high, in the sense that the estimated eccentricity tends to be larger than the true eccentricity. As with most non-trivial observables, a simple…

Solar and Stellar Astrophysics · Physics 2011-01-19 David W. Hogg , Adam D. Myers , Jo Bovy

The solar tachocline at the bottom of the convection zone is an important region for the dynamics of the Sun and the solar dynamo. In this region, the sound speed inferred by global helioseismology exhibits a bump of approximately 0.4%…

Solar and Stellar Astrophysics · Physics 2009-09-28 Junwei Zhao , Thomas Hartlep , A. G. Kosovichev , N. N. Mansour

A new time--distance far-side imaging technique was recently developed by utilizing multiple multi-skip acoustic waves. The measurement procedure is applied to 11 years of Doppler observations from the Solar Dynamics Observatory /…

Solar and Stellar Astrophysics · Physics 2022-01-05 Junwei Zhao , Grace Y. Jing , Ruizhu Chen

Inverse problems are often ill-posed, with solutions that depend sensitively on data. In any numerical approach to the solution of such problems, regularization of some form is needed to counteract the resulting instability. This paper is…

Numerical Analysis · Mathematics 2009-09-14 S. L. Cotter , M. Dashti , A. M. Stuart

Helioseismology studies the structure and dynamics of the Sun's interior by observing oscillations on the surface. These studies provide information about the physical processes that control the evolution and magnetic activity of the Sun.…

Solar and Stellar Astrophysics · Physics 2015-05-27 Alexander G. Kosovichev

We formulate, and present a numerical method for solving, an inverse problem for inferring parameters of a deterministic model from stochastic observational data (quantities of interest). The solution, given as a probability measure, is…

Numerical Analysis · Mathematics 2021-05-04 T. Butler , J. D. Jakeman , T. Wildey

Magnetohydrodynamic (MHD) wave activity is ubiquitous in the solar atmosphere. MHD seismology aims to determine difficult to measure physical parameters in solar atmospheric magnetic and plasma structures by a combination of observed and…

Solar and Stellar Astrophysics · Physics 2015-06-04 Inigo Arregui

Inverse problems in physical or biological sciences often involve recovering an unknown parameter that is random. The sought-after quantity is a probability distribution of the unknown parameter, that produces data that aligns with…

Machine Learning · Statistics 2024-10-02 Qin Li , Maria Oprea , Li Wang , Yunan Yang

The study of solar oscillations (helioseismology) has been a very successful method of researching the Sun. Helioseismology teaches us about the structure and mean properties of the Sun. Together with mid-resolution data, the local…

Solar and Stellar Astrophysics · Physics 2021-10-20 David Korda , Michal Švanda , Thierry Roudier

Local helioseismology has so far relied on semi-analytical methods to compute the spatial sensitivity of wave travel times to perturbations in the solar interior. These methods are cumbersome and lack flexibility. Here we propose a…

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…

Well-calibrated probabilistic regression models are a crucial learning component in robotics applications as datasets grow rapidly and tasks become more complex. Unfortunately, classical regression models are usually either probabilistic…

Machine Learning · Computer Science 2023-09-12 Hany Abdulsamad , Peter Nickl , Pascal Klink , Jan Peters

Helioseismic inferences of large-scale flows in the solar interior necessitate accounting for the curvature of the Sun, both in interpreting systematic trends introduced in measurements as well as the sensitivity kernel that relates…

Solar and Stellar Astrophysics · Physics 2020-12-23 Jishnu Bhattacharya