Scattering of a plane electromagnetic wave by a generalized Luneburg sphere-Part 2: Wave scattering and time-domain scattering

•Computed scattering by a radially-inhomogeneous sphere using wave theory.•Considered MDRs of a radially-inhomogeneous sphere.•Analyzed scattering using time domain results.•Separated diffraction from transmission for edgeless spheres.

We calculated scattering of an electromagnetic plane wave by a radially inhomogeneous particle and a radially inhomogeneous bubble when the square of the refractive index profile is parabolic as a function of radius. Such a particle or bubble is called a generalized Luneburg lens. A wide variety of scattering phenomena can occur, depending on the value of the two adjustable parameters of the parabola. These phenomena, including transmission rainbows, the weak caustic for near-critical-angle scattering by a bubble, surface orbiting, the interior orbiting paths of morphology-dependent resonances, and the separation of diffraction are studied here using wave theory and time domain scattering. These phenomena are also compared with their appearance or absence for scattering by a homogeneous sphere.