Numerical Modeling of Solar Convection and Oscillations in Magnetic Regions

Solar observations show that the spectra of turbulent convection and oscillations significantly change in magnetic regions, resulting in interesting phenomena, such as high-frequency "acoustic halos" around active regions. In addition, recent observations from SOHO/MDI revealed significant changes of the wave properties in inclined magnetic field regions of sunspots, which affect helioseismic inferences. We use realistic 3D radiative MHD numerical simulations to investigate properties of solar convection and excitation and propagation of oscillations in magnetic regions. A new feature of these simulations is implementation of a dynamic sub-grid turbulence model, which allows more accurate description of turbulent dissipation and wave excitation. We present the simulation results for a wide range of the field strength and inclination in the top 6 Mm layer of the convection zone. The results show interesting and unexpected effects in the dynamics and large-scale organization of the magnetoconvection (including traveling waves and shearing flows), and also changes in the excitation properties and spectrum of oscillations, suggesting an explanation of the acoustic "halos" observed above the acoustic cut-off frequency.