Scattering of waves from a distribution of magnetic dipoles in a plasma

Spherules of pure magnetite, with radii ≲10 micron and number density 10^-5 cm^-3 are known to be present in the Earth's magnetosphere. Rotating charged dust particles, known to exist in many space environments, also constitute a distribution of magnetic dipoles. We consider the case when these particles are in an ambient plasma and calculate the scattering cross-section for an electromagnetic wave. It is found that enhancements over scattering from plasma thermal fluctuations are possible when the dipoles are aligned in an external magnetic field (e.g. the Earth's field) for waves of wavelength much larger than the plasma Debye length.