  The effect of compressibility on the onset of nonhelical turbulent dynamo
action is investigated using both direct simulations as well as simulations
with shock-capturing viscosities, keeping however the regular magnetic
diffusivity. It is found that the critical magnetic Reynolds number increases
from about 35 in the subsonic regime to about 70 in the supersonic regime. In
the high resolution direct simulations the shock structures are much sharper
than in the low resolution shock-capturing simulations. Nevertheless, the
magnetic field looks roughly similar in both cases and does not show shock
structures. Similarly, the onset of dynamo action is not significantly affected
by the shock-capturing viscosity.
