Two-scale integrators with high accuracy and long-time conservations for the nonlinear Klein-Gordon equation in the nonrelativistic limit regime

Fuente: arXiv
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Autores principales: Wang, Bin, Miao, Zhen, Jiang, Yaolin
Formato: Preprint
Publicado: 2022
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author Wang, Bin
Miao, Zhen
Jiang, Yaolin
author_facet Wang, Bin
Miao, Zhen
Jiang, Yaolin
contents In this paper, we are concerned with two-scale integrators for the non-relativistic Klein--Gordon (NRKG) equation with a dimensionless parameter $0<\varepsilon\ll 1$, which is inversely proportional to the speed of light. The highly oscillatory property in time of this model corresponds to the parameter $\varepsilon$ and the equation {in the form of $\partial_{tt}u -\fracΔ{\eps^2} u +\frac{1}{\eps^4}u +\fracλ{\varepsilon^2} f(u)=0$} {has a factor $1/\varepsilon^2$ in front of the nonlinearity which means that this part becomes strong when $\varepsilon$ is small. These} two aspects bring significantly numerical burdens in designing numerical methods. {We propose a class of two-scale integrators which is constructed based on some reformulations to the system, Fourier pseudo-spectral method and exponential integrators.} Two practical integrators up to order three and four are constructed by using some symmetric conditions and the stiff order conditions of implicit exponential integrators. The convergence of the obtained integrators is rigorously studied, and it is shown that the uniform accuracy in time is $\mathcal{O}(h^3)$ and $\mathcal{O}(h^4)$ for the time stepsize $h$. The near energy conservation over long times is also established for the multi-stage integrators by using modulated Fourier expansions.
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id arxiv_https___arxiv_org_abs_2205_08185
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Two-scale integrators with high accuracy and long-time conservations for the nonlinear Klein-Gordon equation in the nonrelativistic limit regime
Wang, Bin
Miao, Zhen
Jiang, Yaolin
Numerical Analysis
65M12, 65M15, 65M70
In this paper, we are concerned with two-scale integrators for the non-relativistic Klein--Gordon (NRKG) equation with a dimensionless parameter $0<\varepsilon\ll 1$, which is inversely proportional to the speed of light. The highly oscillatory property in time of this model corresponds to the parameter $\varepsilon$ and the equation {in the form of $\partial_{tt}u -\fracΔ{\eps^2} u +\frac{1}{\eps^4}u +\fracλ{\varepsilon^2} f(u)=0$} {has a factor $1/\varepsilon^2$ in front of the nonlinearity which means that this part becomes strong when $\varepsilon$ is small. These} two aspects bring significantly numerical burdens in designing numerical methods. {We propose a class of two-scale integrators which is constructed based on some reformulations to the system, Fourier pseudo-spectral method and exponential integrators.} Two practical integrators up to order three and four are constructed by using some symmetric conditions and the stiff order conditions of implicit exponential integrators. The convergence of the obtained integrators is rigorously studied, and it is shown that the uniform accuracy in time is $\mathcal{O}(h^3)$ and $\mathcal{O}(h^4)$ for the time stepsize $h$. The near energy conservation over long times is also established for the multi-stage integrators by using modulated Fourier expansions.
title Two-scale integrators with high accuracy and long-time conservations for the nonlinear Klein-Gordon equation in the nonrelativistic limit regime
topic Numerical Analysis
65M12, 65M15, 65M70
url https://arxiv.org/abs/2205.08185