"Cherenkov radiation" of a sound in a Bose condensed gas

In terms of linearized Gross-Pitaevskii equation we have studied the proces s of sound emission arises from a supersonic particle motion in a Bose cond ensed gas. By analogy with the method used for description of Vavilov-Chere nkov phenomenon, we have found a friction work created by the particle gene rated condensate polarization. For comparison we have found radiation inten sity of excitations. Both methods gives the same result. (C) 2001 Published by Elsevier Science B.V.