Electron dynamics in strong and rapidly varying atomic fields

We consider one- and two-electron transitions in highly charged ions (excitation, electron loss, excitation-loss) which occur in relativistic collisions with photons, electrons, protons and neutral atoms. We focus mainly on two topics. The first one is electronic transitions in highly charged ions in collisions with many-electron atoms where the atom represents a strong perturbation which cannot be treated within the first order Born approximation. The second topic concerns a comparative study of processes of excitation and electron loss by photons, electrons and protons. In particular, we consider a highly correlated process of electron loss from a helium-like highly charged ion (initially in the ground state) proceeding with excitation and consequent Auger decay of autoionizing states of the ion.