Abstract :
Lithium depletion in the solar atmosphere can be explained by an intense mixing in the region below the convection zone. Such mixing can be caused by penetrative convection. However, this mechanism is not effective enough because of the small penetrative depth. An additional mechanism of excitation of large-scale vortical flows at the base of the solar convection zone and establishment of a coupled system with penetrative convection can create the necessary conditions for effective mixing. We present three-dimensional numerical simulations that reveal the basic effects in such a system. The excitation of large-scale flows leads to modulation of penetrative convection and establishment of quasistationary large-scale hydrodynamic structures. The depth of the mixing area increases.
