Electromagnetic energy density and velocity in media with anomalous positive dispersion

摘要

The simplest dispersion lows in the dissipative media, the density of energy, and the characteristic velocities of monochromatic wave process: phase, group and energy velocities have been considered. It has been shown that for polar dielectrics with anomalous positive dispersion and Debye low the velocity of energy coincides with the phase velocity, and the group velocity may exceed the velocity of light.