Reflectionless sponge layers for the numerical solution of Maxwell's equations in cylindrical and spherical coordinates

We review the scaling argument used to derive reflectionless wave absorbing layers for use as Absorbing Boundary Conditions (ABC) in numerical solutio ns of the elliptic and hyperbolic Maxwell equations in cylindrical and sphe rical coordinates, and show that thus obtained absorbing layers are describ ed in the time-domain by causal, strongly well-posed hyperbolic systems. Re presentative results are given for scattering by cylinders. Also, we study the reflection of local ABC's in discrete space. (C) 2000 IMACS. Published by Elsevier Science B.V. All rights reserved.