Some peculiarities of the Vavilov-Cherenkov radiation emitted by heavy ions

In the classical paper by Tamm and Frank on the Vavilov-Cherenkov effect the motion of a particle in transparent infinite medium is supposed to be, rectilinear and with strictly constant velocity. Latter Tamm formulated a criterion for tolerable variation of the particle velocity for this effect. For a fast single charged particle moving in a transparent medium, the energy losses are small enough, so the criterion of Tamm is fulfilled for all frequencies corresponding to visible light. However, energy losses of heavy ions moving in a dense medium cannot be considered small. As a result, the decrease in the velocity of heavy ions becomes so large that the Tamm's criterion is strongly violated. The experimental results on the Vavilov-Cherenkov radiation arising from the motion of relativistic heavy ions of 17979Au in the transparent solids and liquids are presented. (author)