Time-harmonic scattering of plane waves from an infinite periodically inhomogeneous medium

Fuente: arXiv
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Main Authors: Hu, Guanghui, Rathsfeld, Andreas, Zhang, Jiayi, Zhang, Ruming
Format: Preprint
Published: 2025
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_version_ 1866911245800570880
author Hu, Guanghui
Rathsfeld, Andreas
Zhang, Jiayi
Zhang, Ruming
author_facet Hu, Guanghui
Rathsfeld, Andreas
Zhang, Jiayi
Zhang, Ruming
contents We propose a new radiation condition for an infinite inhomogeneous two-dimensional medium which is periodic in the vertical direction and remains invariant in the horizontal direction. The classical Rayleigh-expansion radiation condition does not apply to our case, because this would require the medium to be inhomogeneous in a half plane. We utilize the Floquet theory to derive upward/downward wave modes and define radiation conditions by expansions w.r.t. these modes. The downward radiation conditions leads to a downward Dirichlet-to-Neumann map which can be used to truncate the infinite inhomogeneous domain in the vertical direction. So we prove mapping properties of the upward/downward Dirichlet-to-Neumann maps based on the asymptotic behavior of high-order wave modes. Finally, we verify the strong ellipticity of the sesquilinear form corresponding to the new scattering problem and show the unique solvability for all wavenumbers with the exception of a countable set of numbers bounded below by a small positive constant.
format Preprint
id arxiv_https___arxiv_org_abs_2510_14070
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Time-harmonic scattering of plane waves from an infinite periodically inhomogeneous medium
Hu, Guanghui
Rathsfeld, Andreas
Zhang, Jiayi
Zhang, Ruming
Analysis of PDEs
We propose a new radiation condition for an infinite inhomogeneous two-dimensional medium which is periodic in the vertical direction and remains invariant in the horizontal direction. The classical Rayleigh-expansion radiation condition does not apply to our case, because this would require the medium to be inhomogeneous in a half plane. We utilize the Floquet theory to derive upward/downward wave modes and define radiation conditions by expansions w.r.t. these modes. The downward radiation conditions leads to a downward Dirichlet-to-Neumann map which can be used to truncate the infinite inhomogeneous domain in the vertical direction. So we prove mapping properties of the upward/downward Dirichlet-to-Neumann maps based on the asymptotic behavior of high-order wave modes. Finally, we verify the strong ellipticity of the sesquilinear form corresponding to the new scattering problem and show the unique solvability for all wavenumbers with the exception of a countable set of numbers bounded below by a small positive constant.
title Time-harmonic scattering of plane waves from an infinite periodically inhomogeneous medium
topic Analysis of PDEs
url https://arxiv.org/abs/2510.14070