Parametric generation of acoustic-gravity waves in the solar atmosphere

Based on a plane isothermal solar-atmosphere model, we investigate the parametric generation of acoustic-gravity waves (AGWs) in the approximation of a fixed field for vertically propagating disturbances. Both nonpropagating and propagating AGWs are shown to be generated at the difference frequency via the nonlinear interaction of primary waves in the frequency range “forbidden” for the propagation of AGWs during their linear generation. An acoustic wind has been found to be formed in the solar atmosphere at zero difference frequency; its velocity increases with height in inverse proportion to the decreasing ambient density. We study the nonlinear generation of AGWs at the second harmonic during the interaction of disturbances from the forbidden frequency range.