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The time-harmonic Maxwell equations at high wavenumber k in domains with an analytic boundary and impedance boundary conditions are considered. A wavenumber-explicit stability and regularity theory is developed that decomposes the solution…

Numerical Analysis · Mathematics 2023-08-17 Jens M. Melenk , Stefan A. Sauter

Semi-discrete and fully discrete mixed finite element methods are considered for Maxwell-model-based problems of wave propagation in linear viscoelastic solid. This mixed finite element framework allows the use of a large class of existing…

Numerical Analysis · Mathematics 2021-06-16 Hao Yuan , Xiaoping Xie

We present an implicit-explicit (IMEX) scheme for semilinear wave equations with strong damping. By treating the nonlinear, nonstiff term explicitly and the linear, stiff part implicitly, we obtain a method which is not only unconditionally…

Numerical Analysis · Mathematics 2024-07-01 Daniel Eckhardt , Marlis Hochbruck , Barbara Verfürth

A set of semi-analytical techniques based on Fourier analysis is used to solve wave scattering problems in variously shaped waveguides with varying normal admittance boundary conditions. Key components are newly developed conformal mapping…

Mathematical Physics · Physics 2015-06-02 Anders Andersson , Borje Nilsson , Thomas Biro

The paper investigates a variant of semi-implicit spectral deferred corrections (SISDC) in which the stiff, fast dynamics correspond to fast propagating waves ("fast-wave slow-wave problem"). We show that for a scalar test problem with two…

Numerical Analysis · Mathematics 2016-08-18 Daniel Ruprecht , Robert Speck

Numerical climate- and weather-prediction requires the fast solution of the equations of fluid dynamics. Discontinuous Galerkin (DG) discretisations have several advantageous properties. They can be used for arbitrary domains and support a…

Computational Physics · Physics 2020-10-13 Jack D. Betteridge , Thomas H. Gibson , Ivan G. Graham , Eike H. Müller

In this paper, we present a sparse grid-based Monte Carlo method for solving high-dimensional semi-linear nonlocal diffusion equations with volume constraints. The nonlocal model is governed by a class of semi-linear partial…

Numerical Analysis · Mathematics 2025-07-08 Changtao Sheng , Bihao Su , Chenglong Xu

In several geophysical applications, such as full waveform inversion and data modelling, we are facing the solution of inhomogeneous Helmholtz equation. The difficulties of solving the Helmholtz equa- tion are two fold. Firstly, in the case…

Geophysics · Physics 2017-12-27 Nasser Kazemi

The ideal MHD equations are a central model in astrophysics, and their solution relies upon stable numerical schemes. We present an implementation of a new method, which possesses excellent stability properties. Numerical tests demonstrate…

Instrumentation and Methods for Astrophysics · Physics 2011-04-28 Knut Waagan , Christoph Federrath , Christian Klingenberg

In this letter, we focus on designing constant-modulus waveform with discrete phases for the multi-input multi-output (MIMO) radar, where the signal-to-interference-plus-noise ratio (SINR) is maximized in the presence of both the…

Signal Processing · Electrical Eng. & Systems 2018-06-15 Chenglin Ren , Zhaohui Ma , Fan Liu , Weichao Pi , Jianming Zhou

In 1967, Whitham proposed a simplified surface water-wave model which combined the full linear dispersion relation of the full Euler equations with a weakly linear approximation. The equation he postulated which is now called the Whitham…

Computational Physics · Physics 2020-02-20 Evgueni Dinvay , Denys Dutykh , Henrik Kalisch

We develop efficient and high-order accurate solvers for the Helmholtz equation on complex geometry. The schemes are based on the WaveHoltz algorithm which computes solutions of the Helmholtz equation by time-filtering solutions of the wave…

Numerical Analysis · Mathematics 2025-04-07 Daniel Appelo , Jeffrey W. Banks , William D. Henshaw , Donald W. Schwendeman

We propose an explicit-implicit scheme for numerically solving Special Relativistic Radiation Hydrodynamic (RRHD) equations, which ensures a conservation of total energy and momentum (matter and radiation). In our scheme, 0th and 1st moment…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Hiroyuki R. Takahashi , Ken Ohsuga , Yuichiro Sekiguchi , Tsuyoshi Inoue , Kengo Tomida

We propose a novel on-surface radiation condition to approximate the outgoing solution to the Helmholtz equation in the exterior of several impenetrable convex obstacles. Based on a local approximation of the Dirichlet-to-Neumann operator…

Computational Physics · Physics 2021-02-01 Sebastian Acosta

Generalized impedance boundary conditions are effective, approximate boundary conditions that describe scattering of waves in situations where the wave interaction with the material involves multiple scales. In particular, this includes…

Numerical Analysis · Mathematics 2020-05-29 Lehel Banjai , Christian Lubich , Joerg Nick

By using the quantum hydrodynamic and Maxwell equations, we derive nonlinear electron-magnetohydrodynamic (MHD), Hall-MHD, and dust Hall-MHD equations for dense quantum magnetoplasmas. The nonlinear equations include the electromagnetic,…

Plasma Physics · Physics 2015-05-13 N. Shukla , G. Brodin , M. Marklund , P. K. Shukla , L. Stenflo

A rigorous reduction of the many-body wave scattering problem to solving a linear algebraic system is given bypassing solving the usual system of integral equation. The limiting case of infinitely many small particles embedded into a medium…

Mathematical Physics · Physics 2009-11-13 A. G. Ramm

This paper describes a fast direct boundary element method for elastodynamic transmission problems in two dimensions, which can be used for analyzing elastic wave scattering by an inclusion. We develop an efficient solver based on a…

Numerical Analysis · Mathematics 2026-03-24 Yasuhiro Matsumoto , Taizo Maruyama

The interaction of plasma with magnetic field in the partially ionised solar atmosphere is frequently modelled via a single-fluid approximation, which is valid for the case of a strongly coupled collisional media, such as solar photosphere…

Solar and Stellar Astrophysics · Physics 2018-07-18 P. A. González-Morales , E. Khomenko , T. P. Downes , A. de Vicente

In this paper a numerical procedure to simulate low diffusivity scalar turbulence is presented. The method consists of using a grid for the advected scalar with a higher spatial resolutions than that of the momentum. The latter usually…