Abstract

One of the main drivers of the possible effect of cosmic ray particles on atmospheric physics and chemistry is connected to the Induced Atmospheric Ionization (IAI) due to high-energy precipitating particles. IAI by cosmic rays, which can be considerably enhanced during solar proton events, was extensively discussed over the last decade. In most of the recent models, IAI plays a key role on the physics and chemistry of the atmosphere, specifically on minor constituents. It is known that the contribution of galactic cosmic ray particles to ion production in the atmosphere is nearly constant, slightly influenced by the solar activity. On the other hand, the relativistic solar particles could produce a significant excess of ion pair production, particularly over polar caps. This effect is normally strong at short time scales. The sequence of three ground level enhancements GLE 65, 66 & 67 in October–November 2003 gives an unique opportunity to study impact ionization on enhanced manner and extended time scale. Using Monte Carlo simulation and derived solar proton spectra, we computed the ion production and the corresponding ionization effect in the Earth atmosphere in the region of Regener–Pfotzer maximum during the so-called Halloween events in October–November 2003.