Models for the Description of Track Formation

The different models developed to describe track formation induced by swift heavy ions will be presented. The macroscopic ones are the Coulomb explosion model, the bond weakening (BW) model, the exciton self-trapping (STX) model, the concept of reduced electronic energy loss, the analytical thermal spike model, the IDEA (Ionization Diffusion-Explosion-Amorphization) model, the inelastic thermal spike model (i-TS) and to finish microscopic descriptions using molecular dynamic (MD) calculations. All the models were applied to describe the track formation in different kinds of materials (metals, semiconductors or insulators), while additionally the i-TS model and MD calculations were used to describe the sputtering yield. It will be shown that the initial energy deposition plays an important role in the different descriptions and that there is no simple link between the energy deposited in the electronic and later in the atomic system. The large number of models presented here shows by itself that we are far away from a complete description of track formation. So the ambition here is just to give a present status of the different models.