Efficient Computation of Power, Force, and Torque in BEM Scattering Calculations

TL;DR

This paper introduces efficient formulas for calculating power, force, and torque directly from BEM surface currents, simplifying electromagnetic scattering computations without needing to compute scattered fields.

Contribution

The paper presents novel formulas that directly relate BEM surface currents to physical quantities like power, force, and torque, improving computational efficiency.

Findings

Formulas accurately compute power, force, and torque in example geometries.

No need to compute scattered electromagnetic fields, reducing computational complexity.

Open-source software implementations are provided for practical use.

Abstract

We present concise, computationally efficient formulas for several quantities of interest -- including absorbed and scattered power, optical force (radiation pressure), and torque -- in scattering calculations performed using the boundary-element method (BEM) [also known as the method of moments (MOM)]. Our formulas compute the quantities of interest \textit{directly} from the BEM surface currents with no need ever to compute the scattered electromagnetic fields. We derive our new formulas and demonstrate their effectiveness by computing power, force, and torque in a number of example geometries. Free, open-source software implementations of our formulas are available for download online.