Physical events of heavy ion interactions with matter.

Types and severeness of biological effects of heavy ions depend crucially on their physical track structure. Recently considerable progress could be made in simulation on fast digital computers the sequence of primary physical events produced by such ions. Such primary distributions represent e.g. adequate starting points for investigations an subsequent non-homogenous chemical and biological re-actions of biological matter. This paper gives a short review of the present state-of-art in physical track structure research and on its open questions.