The Low-Altitude Ionosphere of the Ice Giant Planets

The study of atmospheric electricity of the lower stratosphere and upper troposphere of the ice giant planets can help to understand several physical phenomena such as cloud formation, lightning generation, aerosols growth, or chemical composition. At these depths, galactic radiation is the main energy source able to ionize the atmospheric constituents and to produce a low altitude ionospheric layer that can be similar in magnitude to the upper ionosphere produced by solar radiation and auroral electrons. The presence of aerosols affects the ion-neutral chemistry by capturing electrons and ions depending on the aerosol size and number density. Here, we present a new one dimensional ionospheric model of Uranus and Neptune able to calculate the number densities of electrons and ions as well as the charging of aerosols between 100 Pa and 4 x 10(5) Pa. Since the results depends upon the amount and size of the atmospheric aerosols, as well as on the flux of the incoming cosmic radiation, several aerosol models, solar-cycle conditions, and the effect of the intrinsic magnetic field are considered.