Kinetic energy dissipation in heavy ion reactions and nuclear matter density oscillations

Mechanism of the dissipation of the kinetic energy in heavy-ion reactions is investigated. It is assumed that collective oscillations of the nuclear matter density are excited predominantly at the initial stage of the reaction. It is shown that the friction coefficient and the induced potential depend on the time explicity. For these quantities, the time for which the asymptotics installs is comparable with the reaction time. To explain the experimentally observable losses of the kinetic energy and the correlations between the mean energy and the deviation angle of the reaction products, a simultaneous account of the time-dependent nuclear interaction potential and the variable friction is essential