The Effect of Ambient Vibrational Nonequilibrium on the Propagation of Acoustic-gravity Waves

This work is a theoretical study of the effect of ambient vibrational nonequilibrium(vibrational or radiative) on the propagation of acoustic and gravity waves in a gas. In the propagation of such waves, nonequilibrium phenomena can manifest themselves in two distinct ways. This follows from the fact that nonequilibrium can exist in either(or both) the ambient and perturbed states of the gas. It is well known that perturbation nonequilibrium always contribute to damping of the waves. The lesser known effects of ambient nonequilibrium are examined here from the point of view of macroscopic gas dynamics. The physical insight obtained in a one-dimensional analysis is applied to the study of the probable effect of vibrational nonequilibrium(ambient and perturbation) on the propagation of acoustic-gravity waves in Earth's upper atmosphere.