The atmosphere above about 100km altitude, in increasing proportions with altitude, consists of electrically charged molecules and atoms that result from the absorption of solar ultraviolet and X-ray radiation. This mixture of charged and neutral atoms and molecules is called a plasma, and the study of irregularities that form in it under the influence of electric and magnetic fields and currents, is important because of its many applications. Not only can we expect to understand and better predict the effects of plasma instabilities on radio communications and ground-satellite transmissions through this region, but it may have application to laboratory studies and in areas such as magnetically confined fusion reactors. The immediate objectives concern understanding large scale waves in the E region of the ionosphere, the heating caused by waves driven by auroral electric fields, and the dynamics of water cluster ions in the polar mesosphere (50-85km altitude) in the very cold conditions which exist there in summer.
