The investigation is focused on the processes associated with the detection of heavy ions of hundreds GeV energy in silicon p+-n-n+ detectors. In the study, the 1D simulation of the electric field and free carrier density evolution in the 238U ion track during the first nanosecond was carried out, which demonstrated the initial appearance of narrow high electric field regions adjacent to the contacts and a strong reduction of the electric field in between. The kinetics of the electron-hole plasma dispersal was assigned to a track polarization within 100 ps followed by a delayed track destruction up to its disappearance. It was shown that the process at the p+ contact was governed by the drift of electrons as a merged fraction of free carriers, which controls the hole current flowing between the track and the p+ contact. The density of the current initiated by the track polarization was evaluated as 8·103 A/cm2.