Computation of ion production rate and short, mid and long term   ionization effect by cosmic rays during Bastille day event
  The galactic cosmic rays are the main source of ionization in the Earth stratosphere and troposphere. The induced by primary cosmic ray particles ionization is important in various processes related to atmospheric physics and chemistry, specifically the minor constituents. The ion production in the atmosphere is enhanced compared to the average following major solar energetic particles events, specifically over the polar caps. During the solar cycle 23 we observed several strong ground level enhancements, one of the strongest among them been the Bastille day event on 14 July 2000. In the work presented here we apply a full Monte Carlo 3-D model in order to compute the cosmic ray induced ionization. The model is based on atmospheric shower simulation with the PLANETOCOSMICS code and the ion production rate is considered as a superposition of cosmic rays with galactic and solar origin. The ion production rate is computed as a function of the altitude above the sea level and the short, mid and long term ionization effect relative to the average due to galactic cosmic rays is computed. 
Alexander Mishev and Peter Velinov
astro-ph.HE physics.space-ph