The propagation of transient wave packets in highly dissipative media

摘要

The group velocity of a wave packet is defined in terms of the central wave number. Because of scale-dependent dissipation, the central wave number migrates to lower values as transient wave packets propagate through dissipative media. The importance of this effect is greater the broader the bandwidth of the wave packet is or the more localized it is spatially. For modest localization, the migration of the central wave number significantly accelerates the vertical motion of wave packets and allows propagation to significantly greater altitudes before packets are substantially dissipated. Wave packets may experience significant attenuation due to dispersion before they begin to experience strong viscous dissipation.