Energy Propagation in Linear Hyperbolic Systems in the Presence of Dissipation

Abstract

The concept of energy velocity for linear dispersive waves is usually given for a normal mode solution of the system as the ratio between the mean energy flux and the mean energy density; it is usually referred to as the energy — flux velocity. In the absence of dissipation this velocity is known to coincide with the corresponding group velocity. When dispersion is accompanied by dissipation, this interpretation is not correct since the group velocity loses its original meaning and can assume nonphysical values.