Geometric properties of acoustic waves generated by a point source in solar-like interior: effects of acoustic cut-off frequency

Acoustic waves generated by a point source in stratified plasma are considered in this paper. Analytical parametric solution for monochromatic source is derived for plane-parallel polytrope model of the solar interior. The solution is used to gain insight into the properties of the generated wavefront as a function of excitation frequency and depth. A slowly varying pressure perturbation moving in upper layers of solar photosphere with supersonic speed is also considered. It is shown to excite acoustic waves putting certain restrictions upon their geometry of the generated wavefront. The results are discussed in relation to flare generated sunquakes.