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Global-scale inertial modes of oscillations have been recently observed on the Sun. They might play an important dynamic and diagnostic role for the Sun. This work aims to assess the validity of simplifying assumptions in the equation of…

Solar and Stellar Astrophysics · Physics 2025-04-23 Suprabha Mukhopadhyay , Yuto Bekki , Xiaojue Zhu , Laurent Gizon

The operation of the solar dynamo, with all of its remarkable spatio-temporal ordering, remains an outstanding problem of modern solar physics. A number of mechanisms that might plausibly contribute to its operation have been proposed, but…

In groundwater hydrology, geophysical imaging holds considerable promise for improving parameter estimation, due to the generally high resolution and spatial coverage of geophysical data. However, inversion of geophysical data alone cannot…

Geophysics · Physics 2017-01-06 T. Lochbühler , J. Doetsch , R. Brauchler , N. Linde

A new inversion method for determining near-surface shear currents from a measured wave spectrum is introduced. The method is straightforward to implement and starts from the existing state-of-the-art technique of assigning effective depths…

Atmospheric and Oceanic Physics · Physics 2020-02-19 Benjamin K. Smeltzer , Eirik Æsøy , Anna Ådnøy , Simen Å. Ellingsen

Condition monitoring of induction motor has been widely researched over recent years due to its ability to monitor operating characteristics and the health status of induction motor. Various methods have been used to monitor induction…

Systems and Control · Electrical Eng. & Systems 2021-10-15 Rayyan Bin Fairuz

Using data from the Michelson Doppler Imager (MDI) instrument on board the Solar and Heliospheric Observatory (SOHO), we study the large-scale velocity fields in the outer part of the solar convection zone using the ring diagram technique.…

Astrophysics · Physics 2015-06-24 Sarbani Basu , H. M. Antia

Mode fitting or "peak-bagging" is an important procedure in helioseismology allowing one to determine the various mode parameters of solar oscillations. Here we describe a way of reducing the systematic bias in the fits of certain mode…

Solar and Stellar Astrophysics · Physics 2011-02-11 S. T. Fletcher , W. J. Chaplin , Y. Elsworth , R. New

We have carried out inversions of travel times as measured by Gizon et al. (2020) to infer the internal profile of the solar meridional circulation (MC). A linear inverse problem has been solved by the regularized least-squares method with…

Solar and Stellar Astrophysics · Physics 2024-06-19 Yoshiki Hatta , Hideyuki Hotta , Takashi Sekii

Despite the strong evidence that the peaks in the spectrum of solar oscillations are asymmetric, most determinations of mode frequencies have been based on fits of symmetric Lorentzian profiles to the Fourier or power spectra of oscillation…

We apply our method of indirect integration, described in Part I, at fourth order, to the radial fall affected by the self-force. The Mode-Sum regularisation is performed in the Regge-Wheeler gauge using the equivalence with the harmonic…

General Relativity and Quantum Cosmology · Physics 2016-03-22 P. Ritter , S. Aoudia , A. Spallicci , S. Cordier

Imaging systems based on a narrow-band tunable filter are used to obtain Doppler velocity maps of solar features. These velocity maps are created by taking the difference between the blue- and red-wing intensity images of a chosen spectral…

Solar and Stellar Astrophysics · Physics 2010-09-16 Sreejith Padinhatteeri , R. Sridharan , K. Sankarasubramanian

Measuring the depth variation of the meridional flows is important for understanding the solar cycle, at least according to a number of dynamo models. While attempting to extend the early observations of \citet{giles_thesis} of…

Solar and Stellar Astrophysics · Physics 2012-08-27 Thomas L. Duvall, , Shravan M. Hanasoge

Observations show that propagating magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere. The technique of MHD seismology uses the wave observations combined with MHD wave theory to indirectly infer physical parameters of…

Solar and Stellar Astrophysics · Physics 2015-06-11 M. Goossens , R. Soler , I. Arregui , J. Terradas

Over the past 15 years, our knowledge of the interior of the Sun has tremendously progressed by the use of helioseismic measurements. However, to go further in our understanding of the solar core, we need to measure gravity (g) modes.…

Understanding the governing mechanism of solar magnetism remains an outstanding challenge in astrophysics. Seismology is the most compelling technique with which to infer the internal properties of the Sun and stars. Waves in the Sun,…

Solar and Stellar Astrophysics · Physics 2017-07-31 Shravan M. Hanasoge

Low-m inertial modes have been recently discovered in the Sun's high-latitude regions. In this study, we characterize the observational properties of the m = 1 mode by analyzing time-distance subsurface flow maps. Synoptic flow maps,…

Solar and Stellar Astrophysics · Physics 2025-06-25 Boyang Ding , Junwei Zhao , Ruizhu Chen , Matthias Waidele , Sushant S. Mahajan , Oana Vesa

We determine the response of a uniformly rotating star to tidal perturbations due to a companion. General periodic orbits and parabolic flybys are considered. We evaluate energy and angular momentum exchange rates as a sum of contributions…

Solar and Stellar Astrophysics · Physics 2015-06-15 P. B. Ivanov , J. C. B. Papaloizou , S. V. Chernov

We perform helioseismic holography on realistic solar convection simulations and compare the observed travel-time perturbations with the expected travel times from the horizontal flows in the simulations computed from forward models under…

Astrophysics · Physics 2016-03-28 D. C. Braun , A. C. Birch , D. Benson , R. F. Stein , Å. Nordlund

Tomography can be used to reveal internal properties of a 3D object using any penetrating wave. Advanced tomographic imaging techniques, however, are vulnerable to both systematic and random errors associated with the experimental…

Numerical Analysis · Mathematics 2019-02-08 Anthony P. Austin , Zichao Wendy Di , Sven Leyffer , Stefan M. Wild

We describe, test, and apply a technique to incorporate full-sun, surface flux evolution into an MHD model of the global solar corona. Requiring only maps of the evolving surface flux, our method is similar to that of Lionello et al.…

Solar and Stellar Astrophysics · Physics 2023-10-12 Roberto Lionello , Cooper Downs , Emily I. Mason , Jon A. Linker , Ronald M. Caplan , Pete Riley , Viacheslav S. Titov , Marc L. DeRosa
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