  Understanding radiation-induced defect formation in carbon materials is
crucial for nuclear technology and for the manufacturing of nanostructures with
desired properties. Using first principles molecular dynamics, we perform a
systematic study of the non-equilibrium processes of radiation damage in
graphite. Our study reveals a rich variety of defect structures (vacancies,
interstitials, intimate interstitial-vacancy pairs, and in-plane topological
defects) with formation energies of 5--15 eV. We clarify the mechanisms
underlying their creation and find unexpected preferences for particular
structures. Possibilities of controlled defect-assisted engineering of
nanostructures are analyzed. In particular, we conclude that the selective
creation of two distinct low-energy intimate Frenkel pair defects can be
achieved by using a 90--110 keV electron beam irradiation.
