ACOUSTIC-GRAVITY WAVES NEAR THE TEMPERATURE DISCONTINUITY IN THE SOLAR ATMOSPHERE

The propagation of atmospheric waves near the transition region in the solar atmosphere is studied. The dispersion relation for surface wave s propagating at the temperature discontinuity in a two-layer model at mosphere is derived and analyzed. Exact solutions are found for this r elation. They include various modes that propagate along the boundary. One type of wave has a dispersion relation of the same form as that o f deep water waves. These waves can propagate if their frequency excee ds omega(g), the Brunt-Vaisala frequency for the lower layer. The freq uencies of other surface waves are equal to omega(g) frequencies of ea ch of the two layers. It is also shown that a squeezed mode can propag ate near the boundary. This mode is characterized by the absence of ho rizontal velocity and pressure perturbations. The results are used to interpret observational data for the solar atmosphere.