Dust particle charging and formation of dust structures in the upper atmosphere

We investigate the dust particle charging process in the Earth's upper atmo sphere. Calculating the spectra of solar radiation, we study the influence of the photoelectric effect on the charging process. We show that both posi tively and negatively charged dust particles are present in the upper atmos phere. We consider the mechanisms which can be responsible for the formatio n of dust structures like noctilucent clouds and polar mesosphere summer ec hoes. (C) 2000 MAIK "Nauka/Interperiodica".