The amplitude of solar p-mode oscillations from three-dimensional convection simulations

Abstract

The amplitude of solar p-mode oscillations is governed by stochastic excitation and mode damping, both of which take place in the surface convection zone. However, the time-dependent, turbulent nature of convection makes it difficult to self-consistently study excitation and damping processes through the use of traditional one-dimensional hydrostatic models. To this end, we carried out \textit{ab initio} three-dimensional, hydrodynamical numerical simulations of the solar atmosphere to investigate how p-modes are driven and dissipated in the Sun. The description of surface convection in the simulations is free from the tuneable parameters typically adopted in traditional one-dimensional models. Mode excitation and damping rates are computed based on analytical expressions whose ingredients are evaluated directly from the three-dimensional model. With excitation and damping rates both available, we estimate the theoretical oscillation amplitude and frequency of maximum power, $\nu_{\max}$, for the Sun. We compare our numerical results with helioseismic observations, finding encouraging agreement between the two. The numerical method presented here provides a novel way to investigate the physical processes responsible for mode driving and damping, and should be valid for all solar-type oscillating stars.