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With increasing quantity and quality of solar observations, it becomes essential to account for three-dimensional heterogeneities in wave modeling for seismic data interpretation. In this context, we present a 3D solver of the time-harmonic…

In this article, we study the damped time-harmonic Galbrun's equation which models solar and stellar oscillations. We introduce and analyze hybrid discontinuous Galerkin discretizations (HDG) that are stable and optimally convergent for all…

Numerical Analysis · Mathematics 2025-11-17 Martin Halla , Christoph Lehrenfeld , Tim van Beeck

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…

This study introduces a hybridizable discontinuous Galerkin (HDG) method for simulating low-frequency wave propagation in poroelastic media. We present a novel four-field variational formulation and establish its well-posedness and energy…

Numerical Analysis · Mathematics 2025-03-12 Salim Meddahi

Helioseismic holography is an imaging technique used to study heterogeneities and flows in the solar interior from observations of solar oscillations at the surface. Holograms contain noise due to the stochastic nature of solar…

Solar and Stellar Astrophysics · Physics 2018-12-12 Laurent Gizon , Damien Fournier , Dan Yang , Aaron C. Birch , Hélène Barucq

The interaction of light with metallic nanostructures produces a collective excitation of electrons at the metal surface, also known as surface plasmons. These collective excitations lead to resonances that enable the confinement of light…

This work is concerned with implementing the hybridizable discontinuous Galerkin (HDG) method to solve the linear anisotropic elastic equation in the frequency domain. First-order formulation with the compliance tensor and Voigt notation…

Analysis of PDEs · Mathematics 2024-04-29 Ha Pham , Florian Faucher , Hélène Barucq

In this paper, we develop hybridized discontinuous Galerkin (HDG) methods for poroelastic wave equations. We first rewrite the governing equations to a first-order symmetric hyperbolic system in order to use dual mixed formulations for…

Numerical Analysis · Mathematics 2026-05-08 Jeonghun J. Lee , Manuel A. Sanchez

In this paper, we perform non-linear minimization using the Hybridizable Discontinuous Galerkin method (HDG) for the discretization of the forward problem, and implement the adjoint-state method for the computation of the functional…

Analysis of PDEs · Mathematics 2020-09-10 Florian Faucher , Otmar Scherzer

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…

The two-fluid plasma model has a wide range of timescales which must all be numerically resolved regardless of the timescale on which plasma dynamics occurs. The answer to solving numerically stiff systems is generally to utilize…

Numerical Analysis · Mathematics 2024-05-06 Andrew Ho , Uri Shumlak

We present a 3-dimensional (3D) numerical solver of the linearized compressible Euler equations (GALE -- Global Acoustic Linearized Euler), used to model acoustic oscillations throughout the solar interior. The governing equations are…

Solar and Stellar Astrophysics · Physics 2021-03-01 Andrey M. Stejko , Alexander G. Kosovichev , Nagi N. Mansour

Solving real-world nonlinear semiconductor device problems modeled by the drift-diffusion equations coupled with the Poisson equation (also known as the Poisson-Nernst-Planck equations) necessitates an accurate and efficient numerical…

Numerical Analysis · Mathematics 2024-09-19 Qingyuan Shi , Yongyong Cai , Chijie Zhuang , Bo Lin , Dan Wu , Rong Zeng , Weizhu Bao

Discontinuous Galerkin (DG) discretizations with exact representation of the geometry and local polynomial degree adaptivity are revisited. Hybridization techniques are employed to reduce the computational cost of DG approximations and…

Numerical Analysis · Mathematics 2019-08-20 Matteo Giacomini , Ruben Sevilla

The high-order numerical solution of the non-linear shallow water equations (and of hyperbolic systems in general) is susceptible to unphysical Gibbs oscillations that form in the proximity of strong gradients. The solution to this problem…

Numerical Analysis · Mathematics 2016-07-18 Simone Marras , Michal A. Kopera , Emil M. Constantinescu , Jenny Suckale , Francis X. Giraldo

Solar oscillations can be modeled by Galbrun's equation which describes Lagrangian wave displacement in a self-gravitating stratified medium. For spherically symmetric backgrounds, we construct an algorithm to compute efficiently and…

Solar and Stellar Astrophysics · Physics 2024-09-09 Ha Pham , Florian Faucher , Damien Fournier , Hélène Barucq , Laurent Gizon

A Continuous Galerkin method-based approach is presented to compute the seismic normal modes of rotating planets. Special care is taken to separate out the essential spectrum in the presence of a fluid outer core using a polynomial…

Computational Physics · Physics 2021-09-28 Jia Shi , Ruipeng Li , Yuanzhe Xi , Yousef Saad , Maarten V. de Hoop

Helioseismology is the study of the solar interior using observations of oscillations at the surface. It suffers from systematic errors, such as a center-to-limb error in travel-time measurements. Understanding these errors requires a good…

Solar and Stellar Astrophysics · Physics 2021-10-04 N. M. Kostogryz , D. Fournier , L. Gizon

This paper develops the hybridizable discontinuous Galerkin (HDG) method for the Ostrovsky equation, a nonlinear dispersive wave equation featuring both third-order dispersion and a nonlocal antiderivative term with Coriolis effect. On a…

Numerical Analysis · Mathematics 2026-02-17 Mukul Dwivedi , Andreas Rupp

This paper presents a fully discrete numerical scheme for one-dimensional nonlocal wave equations and provides a rigorous theoretical analysis. To facilitate the spatial discretization, we introduce an auxiliary variable analogous to the…

Numerical Analysis · Mathematics 2025-07-15 Qiang Du , Kui Ren , Lu Zhang , Yin Zhou
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