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

In the classical paper by Tamm and Frank on the Vavilov-Cherenkov effect th e motion of a particle in transparent infinite medium is supposed to be, re ctilinear and with strictly constant velocity. Later Tamm formulated a crit erion 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 freq uencies corresponding to visible light. However, energy losses of heavy ion s moving in a dense medium cannot be considered small. As a result, the dec rease in the velocity of heavy ions becomes so large that the Tamm's criter ion is strongly violated. The experimental results on the Vavilov-Cherenkov radiation arising from the motion of relavistic heavy ions of Au-179(79) i n the transparent solids and liquides are presented.