  We present the results of analytical modelling of fast-mode
magnetohydrodynamic wave propagation near a 2D magnetic null point. We consider
both a linear wave and a weak shock and analyse their behaviour in cold and
warm plasmas. We apply the nonlinear geometrical acoustics method based on the
Wentzel-Kramers-Brillouin approximation. We calculate the wave amplitude, using
the ray approximation and the laws of solitary shock wave damping. We find that
a complex caustic is formed around the null point. Plasma heating is
distributed in space and occurs at a caustic as well as near the null point due
to substantial nonlinear damping of the shock wave. The shock wave passes
through the null point even in a cold plasma. The complex shape of the wave
front can be explained by the caustic pattern.
