Effect of Dissipation & Diffusion on the Propagation of Atmospheric Gravity Waves in Thermosphere

Abstract

An attempt has been made to investigate the extent to which diffusion, viscosity, thermal conduction and ion drag, influence the propagation of atmospheric gravity waves at the thermospheric heights. The perturbation in the electron density is calculated when the diffusion processes arc taken into account and it is found that the diffusion can be ignored only when the wave period is less than about 5 'min. The viscosity is responsible for damping the slow waves for which the Boussinesq approximation is valid and the wavelength is small. Thermal conduction is more important in damping waves having periods near the Brunt period. The effect of ion drag depends largely on the frequency and is highly complex.