Introduction

Let's simulate the propagation of sound wave when magnetic field exists.

[Initial Condition] We assume isotropic interstellar gas with constant density and constant magnetic field (which has inclination angle 60 degree to the vertical direction of the screen) with 0.5 plasma beta. Perturbation is given as 10% pressure increase at the origin and followed its wave propagation. In the figure, color shows density, arrows show velocity, and lines show magnetic field lines. Bright region has high density and dark region has low density.

[Propagation Stage] Wave propagate faster toward vertical direction of the magnetic field than parallel direction.