Perfectly matched layer

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The '''perfectly matched layer''' ('''PML''') approach to implementing absorbing boundary conditions in FDTD codes was proposed by Berenger in 1994 (see [http://dx.doi.org/10.1006/jcph.1994.1159]). The '''perfectly matched layer''' ('''PML''') approach to implementing absorbing boundary conditions in FDTD codes was proposed by Berenger in 1994 (see [http://dx.doi.org/10.1006/jcph.1994.1159]).
The approach involves surrounding the computational cell with a medium that in theory absorbs without any reflection electromagnetic waves at all frequencies and angles of incidence. Berenger showed that such a medium can be constructed as a lossy anisotropic dielectric with electric and magnetic conductivities of equal magnitude. (Of course, the magnetic conductivity requirement makes this an unphysical medium.) The approach involves surrounding the computational cell with a medium that in theory absorbs without any reflection electromagnetic waves at all frequencies and angles of incidence. Berenger showed that such a medium can be constructed as a lossy anisotropic dielectric with electric and magnetic conductivities of equal magnitude. (Of course, the magnetic conductivity requirement makes this an unphysical medium.)
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 +The finite-difference implementation of PML requires the conductivities to be turned on gradually over a distance of a few grid points to avoid numerical reflections from the discontinuity.

Revision as of 18:48, 7 November 2005

The perfectly matched layer (PML) approach to implementing absorbing boundary conditions in FDTD codes was proposed by Berenger in 1994 (see [1]). The approach involves surrounding the computational cell with a medium that in theory absorbs without any reflection electromagnetic waves at all frequencies and angles of incidence. Berenger showed that such a medium can be constructed as a lossy anisotropic dielectric with electric and magnetic conductivities of equal magnitude. (Of course, the magnetic conductivity requirement makes this an unphysical medium.)

The finite-difference implementation of PML requires the conductivities to be turned on gradually over a distance of a few grid points to avoid numerical reflections from the discontinuity.

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