Splitting algorithms for paraxial and Itô-Schrödinger models of wave propagation in random media

Fuente: arXiv
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Main Authors: Bal, Guillaume, Nair, Anjali
Format: Preprint
Published: 2025
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author Bal, Guillaume
Nair, Anjali
author_facet Bal, Guillaume
Nair, Anjali
contents This paper introduces a full discretization procedure to solve wave beam propagation in random media modeled by a paraxial wave equation or an Itô-Schrödinger stochastic partial differential equation. This method bears similarities with the phase screen method used routinely to solve such problems. The main axis of propagation is discretized by a centered splitting scheme with step $Δz$ while the transverse variables are treated by a spectral method after appropriate spatial truncation. The originality of our approach is its theoretical validity even when the typical wavelength $θ$ of the propagating signal satisfies $θ\llΔz$. More precisely, we obtain a convergence of order $Δz$ in mean-square sense while the errors on statistical moments are of order $(Δz)^2$ as expected for standard centered splitting schemes. This is a surprising result as splitting schemes typically do not converge when $Δz$ is not the smallest scale of the problem. The analysis is based on equations satisfied by statistical moments in the Itô-Schrödinger case and on integral (Duhamel) expansions for the paraxial model. Several numerical simulations illustrate and confirm the theoretical findings.
format Preprint
id arxiv_https___arxiv_org_abs_2503_00633
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Splitting algorithms for paraxial and Itô-Schrödinger models of wave propagation in random media
Bal, Guillaume
Nair, Anjali
Numerical Analysis
Mathematical Physics
Analysis of PDEs
Probability
This paper introduces a full discretization procedure to solve wave beam propagation in random media modeled by a paraxial wave equation or an Itô-Schrödinger stochastic partial differential equation. This method bears similarities with the phase screen method used routinely to solve such problems. The main axis of propagation is discretized by a centered splitting scheme with step $Δz$ while the transverse variables are treated by a spectral method after appropriate spatial truncation. The originality of our approach is its theoretical validity even when the typical wavelength $θ$ of the propagating signal satisfies $θ\llΔz$. More precisely, we obtain a convergence of order $Δz$ in mean-square sense while the errors on statistical moments are of order $(Δz)^2$ as expected for standard centered splitting schemes. This is a surprising result as splitting schemes typically do not converge when $Δz$ is not the smallest scale of the problem. The analysis is based on equations satisfied by statistical moments in the Itô-Schrödinger case and on integral (Duhamel) expansions for the paraxial model. Several numerical simulations illustrate and confirm the theoretical findings.
title Splitting algorithms for paraxial and Itô-Schrödinger models of wave propagation in random media
topic Numerical Analysis
Mathematical Physics
Analysis of PDEs
Probability
url https://arxiv.org/abs/2503.00633