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200 papers

The radiating part of a circular acoustic source is determined on the basis of an exact analysis of the radiation properties of a source with angular dependence $\exp \J n\theta$ and arbitrary radial dependence. It is found that the number…

Fluid Dynamics · Physics 2010-05-12 Michael Carley

Faraday rotation measure (RM) synthesis is an important tool to study and analyze galactic and extra-galactic magnetic fields. Since there is a Fourier relation between the Faraday dispersion function and the polarized radio emission, full…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 Feng Li , Shea Brown , Tim J. Cornwell , Frank de Hoog

This work examines the physical effect of the edge-induced acoustic radiation force and torque on an acoustically radiating circular source, located near a rigid corner. Assuming harmonic (linear) radiating waves of the source, vibrating in…

Classical Physics · Physics 2019-12-03 F. G. Mitri

Source extension is a reformulation of inverse problems in wave propagation, that at least in some cases leads to computationally tractable iterative solution methods. The core subproblem in all source extension methods is the solution of a…

Numerical Analysis · Mathematics 2022-04-01 William W. Symes

Rotation measure synthesis allows the estimation of Faraday dispersion via a Fourier transform and is the primary tool to probe cosmic magnetic fields. We show this can be considered mathematically equivalent to the one dimensional…

Instrumentation and Methods for Astrophysics · Physics 2020-05-13 Luke Pratley , Melanie Johnston-Hollitt

A rigorous mathematical model and an efficient computational method are proposed to solving the inverse elastic surface scattering problem which arises from the near-field imaging of periodic structures. We demonstrate how an enhanced…

Analysis of PDEs · Mathematics 2017-12-08 Huaian Diao , Peijun Li , Xiaokai Yuan

This paper is devoted to the inverse problem of recovering the unknown distributed flux on an inaccessible part of boundary using measurement data on the accessible part. We establish and verify a variational source condition for this…

Analysis of PDEs · Mathematics 2019-02-20 De-Han Chen , Yousept Irwin , Jun Zou

We consider the inverse scattering problem for inhomogeneous media of compact support governed by the fractional s-Helmholtz equation, with $0<s<1$, in dimensions $d=1,2,3$. In particular, we study the determination of the support of the…

Analysis of PDEs · Mathematics 2026-04-30 Dana Zilberberg

This paper is devoted to the uniqueness of inverse acoustic scattering problems with the modulus of near-field data. By utilizing the superpositions of point sources as the incident waves, we rigorously prove that the phaseless near-fields…

Analysis of PDEs · Mathematics 2019-05-22 Deyue Zhang , Fenglin Sun , Yukun Guo , Hongyu Liu

This paper concerns the reconstruction of a diffusion coefficient in an elliptic equation from knowledge of several power densities. The power density is the product of the diffusion coefficient with the square of the modulus of the…

Analysis of PDEs · Mathematics 2012-03-07 Guillaume Bal , Eric Bonnetier , Francois Monard , Faouzi Triki

We demonstrate theoretically that acoustic forces acting on inhomogeneous fluids can be used to pattern and manipulate solute concentration fields into spatio-temporally controllable configurations stabilized against gravity. A theoretical…

Fluid Dynamics · Physics 2017-03-29 Jonas T. Karlsen , Henrik Bruus

This paper is concerned with an inverse random source problem for the three-dimensional time-harmonic Maxwell equations. The source is assumed to be a centered complex-valued Gaussian vector field with correlated components, and its…

Analysis of PDEs · Mathematics 2020-02-21 Peijun Li , Xu Wang

Image reconstruction in photoacoustic tomography relies on an accurate knowledge of the speed of sound in the target. However, the speed of sound distribution is not generally known, which may result in artefacts in the reconstructed…

Medical Physics · Physics 2025-11-06 Miika Suhonen , Felix Lucka , Aki Pulkkinen , Simon Arridge , Ben Cox , Tanja Tarvainen

Faraday Rotation Measure (RM) Synthesis, as a method for analyzing multi-channel observations of polarized radio emission to investigate galactic magnetic fields structures, requires the definition of complex polarized intensity in the…

Astrophysics of Galaxies · Physics 2015-05-14 P. Frick , D. Sokoloff , R. Stepanov , R. Beck

The aim of the study is to demonstrate that some methods are more relevant for implementing the Real-Time Nearfield Acoustic Holography than others. First by focusing on the forward propagation problem, different approaches are compared to…

Classical Physics · Physics 2008-10-13 Jean-Hugh Thomas , Vincent Grulier , Sébastien Paillasseur , Jean-Claude Pascal

This investigation is concerned with the 2D acoustic scattering problem of a plane wave propagating in a non-lossy fluid host and soliciting a linear, isotropic, macroscopically-homogeneous, lossy, flat-plane layer in which the mass density…

Applied Physics · Physics 2019-05-01 Armand Wirgin

We used the Pixelised Wavelet Filtering (PWF) method to compute narrow-band power maps of SDO/AIA imaging datasets in the 1700 \AA{}, 1600 \AA{} and 304 \AA{} bandpasses that correspond to different heights. The cut-off frequency was…

Solar and Stellar Astrophysics · Physics 2014-04-15 Ding Yuan , R. Sych , V. E. Reznikova , V. M. Nakariakov

Faraday Rotation Measure (RM) synthesis requires the recovery of the Faraday Dispersion Function (FDF) from measurements restricted to limited wavelength ranges, which is an ill-conditioned deconvolution problem. Here, we propose a novel…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 M. Andrecut

Consider a time-harmonic elastic point source incident on a bounded obstacle which is embedded in an open space filled with a homogeneous and isotropic elastic medium. This paper is concerned with the inverse problem of recovering the…

Analysis of PDEs · Mathematics 2025-06-02 Chun Liu , Guanghui Hu , Tao Yin , Bo Zhang

Waveform inversion is theoretically a powerful tool to reconstruct subsurface structures, but a usually encountered problem is that accurate sources are very rare, causing the computation unstable and divergent. This challenging problem,…

Geophysics · Physics 2024-07-12 Han Yu