On the Half-Space Matching method for real wavenumbers

Anne-Sophie Bonnet-BenDhia, Simon Chandler-Wilde and Sonia Fliss
Publication type:
Paper in peer-reviewed journals
SIAM Journal on Applied Mathematics, vol. 82(4)
assets/images/icons/icon_arxiv.png 2111.06793
The Half-Space Matching (HSM) method has recently been developed as a new method for the solution of 2D scattering problems with complex backgrounds, providing an alternative to Perfectly Matched Layers (PML) or other artificial boundary conditions. Based on half-plane representations for the solution, the scattering problem is rewritten as a system coupling (1) a standard finite element discretisation localised around the scatterer and (2) integral equations whose unknowns are traces of the solution on the boundaries of a finite number of overlapping half-planes contained in the domain. While satisfactory numerical results have been obtained for real wavenumbers, well-posedness and equivalence of this HSM formulation to the original scattering problem have been established only for complex wavenumbers. In the present paper we show, in the case of a homogeneous background, that the HSM formulation is equivalent to the original scattering problem also for real wavenumbers, and so is well-posed, provided the traces satisfy radiation conditions at infinity analogous to the standard Sommerfeld radiation condition. As a key component of our argument we show that, if the trace on the boundary of a half-plane satisfies our new radiation condition, then the corresponding solution to the half-plane Dirichlet problem satisfies the Sommerfeld radiation condition in a slightly smaller half-plane. We expect that this last result will be of independent interest, in particular in studies of rough surface scattering.
    author={Anne-Sophie Bonnet-BenDhia and Simon Chandler-Wilde and Sonia 
           Fliss },
    title={On the Half-Space Matching method for real wavenumbers },
    journal={SIAM Journal on Applied Mathematics },
    year={2022 },
    volume={82(4) },