Influence of the solar atmosphere on the p-mode eigenoscillations

An asymptotic theory of global adiabatic p-modes is developed, taking into account the influence of the solar atmosphere. It is shown that waves of th e whole frequency range nu approximate to 2-10 mHz may reach the chromosphe re-corona transition region (CCTR) by means of a tunneling through the atmo spheric barriers. The primary acoustic cavity inside the Sun becomes consid erably extended by this way, leading to a change of frequencies: low freque ncies are increased, while high frequencies are decreased. The transition f rom low p-mode frequencies to high peak frequencies (nu greater than or sim ilar to 6 mHz) is smooth. The locations of the turning points are determined from the wave equation f or div (.) (v) over right arrow. It is shown that the internal turning poin t of the acoustic cavity is strongly shifted toward the center of the Sun, while the upper turning point is shifted from the surface to CCTR. That mea ns, the turning points cannot be located in the convective zone. A new comp lex integral dispersion relation for the eigenfrequencies is derived. The i maginary parts of the frequencies indicate a decay of the amplitudes, resul ting from considerable energy losses by tunneling from the main cavity. It is shown that waves with a decaying amplitude (complex frequency) may ex ist in a limited area only, penetration of linear p-modes to the corona is impossible. The CCTR acts as a free surface. We conclude that the p-modes m ay drive forced surface gravity waves at this surface.