MHD Wave Propagation in the Neighbourhood of Coronal Null Points.

James McLaughlin,   University of St Andrews

In the low $\beta$ solar corona, the nature of fast magnetoacoustic and Alfv\'en waves is investigated.
It is found that when coronal null points exist, the fast wave is attracted to such points and the front of
the wave slows down as it approaches the null point, causing the current density to accumulate there and rise rapidly.
    Ohmic dissipation will extract the energy in the wave at this point.
This illustrates that coronal null points play an important role in the rapid dissipation of fast magnetoacoustic waves.
The Alfv\'en wave behaves in a different manner in that the wave energy is dissipated along the separatrices.
 However, the phenomenon of dissipating the majority of the wave energy at a specific place is a feature of both wave types.