Understanding the optical theorem of scattering: Scattering surface area against scattering cross-section, an example with ellipsoidal scattering

Abstract In this paper, we propose using the scattering surface area rather than the scattering cross-section to characterize the scattering behavior of ellipsoidal rigid bodies. We examined the scattering behavior of ellipsoidal rigid bodies, focusing on the relationship between their surface area and total scattering cross-section. Building on the foundational work of Carson Flammer, we utilize the spheroidal coordinate system to derive solutions for both prolate and oblate spheroids. Our analysis reveals that under the long-wavelength approximation, the total scattering cross-section is equivalent to the surface area of the ellipsoid, a relationship that holds true for both small and moderate eccentricities. This finding extends the established optical theorem, previously validated for spherical bodies, to more complex geometries.