NOTE ON THE SCATTERING OF ELECTROMAGNETIC-WAVES FROM CHARGED DUST PARTICLES IN A PLASMA

This note discusses the application of the 'superposition of dressed p articles' concept to the problem of the electron density fluctuations in a plasma with embedded, charged dust grains. It is shown that the d ressed particle approach breaks down when the dust grain separation r( d) and the charge Z become large, and that the scattering cross-sectio n then may be strongly enhanced. The criteria for the transition from one regime to the other are established and applied to the specific pr oblem of scattering of electromagnetic waves from the polar mesopause. The calculations show that it is unlikely that the presence of dust g rains, even when highly charged, can fully account for the observed en hanced polar mesospheric echoes (PMSE).