Transition radiation of moving Abrikosov vortices

We predict that Abrikosov Vortices moving towards the surface of a supercon ductor emit electromagnetic radiation into free space. Passage of a single Vortex line traveling at constant speed v from a superconducting half space , x<0, towards the vacuum half space, x>0, is discussed in detail. The freq uency distribution of the radiated intensity displays a pronounced maximum at microwave frequencies around omega similar or equal to\upsilon(x)\/lambd a, where lambda is the magnetic penetration depth. Coherent motion of a lat tice of flux lines leads to constructive interference and increases the str ength of the radiated power per vortex line by a large factor. Also the rad iation source may be used to measure the velocity of Abrikosov vortices and to determine the magnetic penetration depth.