TRANSITION OF THE LIGHT VELOCITY IN THE VAVILOV-CERENKOV EFFECT

Accelerated and decelerated motions of a. charged point particle insid e medium are studied. It is shown explicitly that in addition to the b remsstrahlung and Cerenkov singular waves: previously unknown electrom agnetic singular wave should be observed. It arises when the charge ve locity coincides with the light velocity in medium. This wave has the same singularity as the Cerenkov one and, therefore, it is more singul ar than the bremsstrahlung wave. The spacetime regions where these wav es exist and conditions under which they appear are determined.