RoAp stars are late-A, chemically peculiar stars with effective temperatures of 7000 - 8000 K; global dipolar-like magnetic fields with strengths between 1 - 10 kG; and pulsation periods of 6 - 20 minutes. Magneto-acoustic oscillations in peculiar A stars are of particular interest due to unique opportunities to study the interaction of pulsations, chemical inhomogeneities, and strong
magnetic fields. In this talk we report the 2D time-dependent non-linear magneto- hydrodynamical simulations of waves in the
atmospheres of these stars. We explore a grid of simulations in a wide parameter space. Our grid covers the stars with magnetic field strengths from 1 to 7 kG, pulsation periods from 6 to 10
minutes and magnetic field inclinations from 0 to 60 degrees, assuming a large-scale dipolar magnetic field. The waves are excited in the sub-surface layers by a vertical driver. We study
the influence of the atmosphere and the magnetic field on the properties of these waves. Our first results pick up some observed
properties of the roAp stars pulsations, such as: rapid growth of the wave amplitude with height, presence of the node surfaces, large variations in pulsation properties depending on the
parameters of the model and a decrease of the amplitude of the pulsations with increasing the magnetic field of the star.