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A multi-domain spectral method for scalar and vectorial Poisson equations with non-compact sources

P. Grandclement·S. Bonazzola·E. Gourgoulhon·J. -A. Marck
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Abstract

We present a spectral method for solving elliptic equations which arise in general relativity, namely three-dimensional scalar Poisson equations, as well as generalized vectorial Poisson equations of the type $Δ\vec{N} + λ\vec{\nabla}(\vec{\nabla}\cdot \vec{N}) = \vec{S}$ with $λ\not= -1$. The source can extend in all the Euclidean space ${\bf R}^3$, provided it decays at least as $r^{-3}$. A multi-domain approach is used, along with spherical coordinates $(r,θ,ϕ)$. In each domain, Chebyshev polynomials (in $r$ or $1/r$) and spherical harmonics (in $θ$ and $ϕ$) expansions are used. If the source decays as $r^{-k}$ the error of the numerical solution is shown to decrease at least as $N^{-2(k-2)}$, where $N$ is the number of Chebyshev coefficients. The error is even evanescent, i.e. decreases as $\exp(-N)$, if the source does not contain any spherical harmonics of index $l\geq k -3$ (scalar case) or $l\geq k-5$ (vectorial case).

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BibTeXRIS

P. Grandclement, S. Bonazzola, E. Gourgoulhon, J. -A. Marck. 2001-02-19. A multi-domain spectral method for scalar and vectorial Poisson equations with non-compact sources. https://doi.org/10.1006/jcph.2001.6734

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