  It has been suggested by radio observations of polarized synchrotron
emissions that downstream magnetic field in some young supernova remnants are
oriented radially. We study magnetic field distribution of turbulent supernova
remnant driven by the Richtmyer-Meshkov instability -- in other words, the
effect of rippled shock -- by using three-dimensional magnetohydrodynamics
simulations. We find that the induced turbulence has radially biased
anisotropic velocity dispersion that leads to a selective amplification of the
radial component of the magnetic field. The Richtmyer-Meshkov instability is
induced by the interaction between the shock and upstream density fluctuations.
Future high-resolution polarization observations can distinguish the following
candidates responsible for the upstream density fluctuations: (i) inhomogeneity
caused by the cascade of large-scale turbulence in the ISM so-called the
big-power-law-in-the-sky, (ii) structures generated by the Drury instability in
the cosmic-ray modified shock, and (iii) fluctuations induced by the non-linear
feedback of the cosmic-ray streaming instability.
