Quasi-electrostatic fields within the atmosphere

Natural electromagnetic fields within the atmosphere which have periods of the order of hours or longer are discussed, emphasizing the electrostatic component of these fields as observed in the lower and middle atmosphere. The origin and properties of conductivity are briefly summarized, and the basic features of the three sources of atmospheric magnetic fields, i.e., thunderstorm electricity and related phenomena, interaction between tidal winds and the ionospheric plasma, and interaction between the solar wind and the magnetosphere, are outlined. Observations made at ground-based stations, balloon altitudes, and ionospheric heights of vertical and horizontal electric fields, the electric field of the Sq current, the electric convection field, and the polar cap field are discussed. Theoretical approaches to the mapping of electric fields in the lower and middle atmosphere and in the magnetosphere, and the description of electric fields and current generation by thunderstorms, tidal winds, and the interaction of the solar wind with the magnetosphere, are reviewed.