LAUSR

The regularities of transition of phase and group velocities from slow surface waves (whose velocities are below the light speed) to fast surface waves (whose velocities are above the light speed) on the plane boundaries of highly conducting media are investigated when the parameters of media vary. It is shown that the structure of waves does not change qualitatively in the case of this transition: the waves remain to be surface ones in contrast to surface waves of dielectric waveguides. The latter ones are transformed into leaking waves or their structure changes in a more complicated way in the case of such transition. A result relating, in particular, to the Zenneck wave is obtained.