  We present two-dimensional simulations of wave propagation in a realistic,
non-stationary model of the solar atmosphere. This model shows a granular
velocity field and magnetic flux concentrations in the intergranular lanes
similar to observed velocity and magnetic structures on the Sun and takes
radiative transfer into account. We present three cases of magneto-acoustic
wave propagation through the model atmosphere, where we focus on the
interaction of different magneto-acoustic wave at the layer of similar sound
and Alfv\'en speeds, which we call the equipartition layer. At this layer the
acoustic and magnetic mode can exchange energy depending on the angle between
the wave vector and the magnetic field vector. Our results show that above the
equipartition layer and in all three cases the fast magnetic mode is refracted
back into the solar atmosphere. Thus, the magnetic wave shows an evanescent
behavior in the chromosphere. The acoustic mode, which travels along the
magnetic field in the low plasma-$\beta$ regime, can be a direct consequence of
an acoustic source within or outside the low-$\beta$ regime, or it can result
from conversion of the magnetic mode, possibly from several such conversions
when the wave travels across a series of equipartition layers.
