Modeling of generation, propagation, and scattering of acoustic waves in the turbulent convection zone of the Sun

We developed a three dimensional linear code for simulations of MHD waves in a gravitationally stratified medium with strong gradients of pressure and density in the presence of non-uniform background magnetic field and background flows. The code is suitable for analysis of excitation, propagation, and transformation of MHD waves in realistic models of sunspots. Such a code can be used for producing artificial data for testing and calibration of heliosesmic inversion techniques used for analysis of data from the space missions SOHO/MDI, HINODE, and SDO/HMI. Comparison of a travel time difference map obtained from simulated artificial data by the standard time-distance techniques shows good agreement with the theoretical prediction calculated in the ray-path approximation. This verifies the consistency and accuracy of time-distance techniques used in the reconstruction of subphotospheric flows. Simulations of MHD waves in a realistic sunspot model calculated by M. Rempel using a non-linear MHD code show the existence of the strong mixture of slow and Alfven waves near the source location (e.g. the magnetostatic background model) and skewness of the wave front of the fast MHD wave (e.g. pure acoustics with background flows).