The magnitude of the power flow density, 10log₁₀|S|, (color), and its direction (arrows) for small-core NPs (a)–(c), and large-core NPs (d)–(f). The power flow density is shown for the concentric, (a) and (d), as well as eccentric, (b)–(c) and (e)–(f), cases. For the latter, the core displacements of x₁₂ = 5 nm, are considered in (b) and (e), whereas x₁₂ = −5 nm in (c) and (f). The results are shown in a square region of 90 × 90 nm². Curves illustrating the cylindrical surfaces of the NP are also shown.