Waves in the Solar Atmosphere. I. The Acoustic Energy Flux.

An extension of Lighthill's theory of aerodynamic generation of sound to stratified atmospheres is used to calculate the upward acoustic energy flux from the solar convection zone. The result is 2 X 1O~ ergs cm2 sec'. In addition the frequency spectrum of the emitted flux is obtained. It rises as c~ (1 < n <2.5) above the critical frequency w~ = 7g/2c, reaches a maximum in a few octaves, and then falls off rapidly. Acoustic emission is very sensitive to the turbulent velocities, and BOhm-Vitense' mixing- length theory gives only a rough model of the solar convection zone. It is also sensitive to the high- frequency tail of the turbulence spectrum. The form of the turbulence energy spectrum is not known and may, in fact, depend on the emission and absorption of acoustic waves. This lack of knowledge yields an uncertainty in the calculated acoustic flux of about an order of magnitude