High-Accuracy Semi-Analytical Method for Solving the Problem of Electromagnetic Wave Scattering by Arbitrary Ensembles of Parallel Circular Cylinders

A method is proposed for solving the two-dimensional problem of electromagnetic wave scattering by a cluster of an arbitrary number of parallel, infinitely long, homogeneous, non-overlapping right circular cylinders.

The cylinders may have arbitrary radii and complex permittivities, and their axes, while remaining parallel, may occupy arbitrary positions in the transverse plane.

The solution is constructed using an analytical expansion of the electromagnetic field in cylindrical harmonics.

Multiple scattering is taken into account by Graf's addition theorem, which leads to a system of linear equations for the expansion coefficients.

This system is solved numerically with condition number monitoring and, when necessary, extended-precision arithmetic, followed by a multistage verification of convergence.

The method provides numerically verified solutions with controlled accuracy over a wide range of parameters, including densely packed subwavelength configurations.

As an example, scattering of a normally incident, linearly polarized monochromatic plane wave by a subwavelength cluster of three identical aluminum nanocylinders (nanowires) is studied.

The scattering, absorption, and extinction cross sections, as well as the scattering indicatrix, are computed and analyzed.

Streamlines of the Poynting vector field are constructed, demonstrating redistribution of the energy flux between the cylinders of the cluster and the formation of localized regions of field enhancement near their surfaces.