Modelling the small-scale plasma response to the presence of heavy aerosol particles

Abstract

Using a one-dimensional, time-dependent model that solves the coupled continuity and momentum equations for an arbitrary number of charged and neutral particles species, we study how the ambient plasma near the polar summer mesopause responds to the presence of heavy aerosol particles. The model includes production and loss of ions and electrons by ionization and recombination, and charging of aerosols due to both electron and ion attachment. In the force balance equation ambipolar diffusion and gravity are included. We find that small-scale aerosol density variations, on length scales relevant to PMSE, cause similar density perturbations in the ambient electron and ion populations. The electron and ion density perturbations are “glued” to the aerosol structures and remain as long as the small-scale aerosol structure persists, which is limited by aerosol particle diffusion and/or evaporation. We find an anticorrelation between electron and aerosol particle densities. In most cases ambipolar diffusion around small-scale structures also leads to an anticorrelation between electron and ion densities, which is in agreement with the majority of rocket observations.