Theoretical aspects of the formation and evolution of charged particle tracks

Theoretical ideas on the formation and evolution of charged particle tracks in a condensed medium are discussed. The historical development of the field is briefly reviewed. The distribution of charged particle energies over quantum states and the volume of the absorbing medium are considered, and conditions for the formation of various track structures (entities) are discussed. The structures of extended heavy-ion tracks are compared for some ion parameters and track characteristics under equal conditions. Relaxation processes in the tracks of multiply charged ions are analyzed. Track effects are considered and possible mechanisms for the formation of chemically active defects in a latent track are described.