High Energy Particles and Atmospheric Processes

   The main ionization source of the Earth middle and lower atmosphere is
   related to energetic particles coming from outer space. Usually it is
   ionization from cosmic rays that is always present in the atmosphere. But
   in the case of a very strong solar eruption some solar energetic particles
   (SEP) can reach middle/lower atmosphere increasing the ionization rate up
   to some orders of magnitude at polar latitudes. By means of case studies
   of solar proton events with different energies of particles and their
   influence on various atmospheric parameters, it will aim to evaluate the
   possible effect of solar (SEP) and galactic (GCR) particles on polar
   microphysical processes. Case studies of extreme SEP events show their
   possible effect on natural variations of aerosol content. However, the
   effect of the additional ambient air ionization on aerosol formation is
   minor, in comparison to temperature effect, and may take place only in
   cold polar atmospheric conditions.