  Radial magnetic fields are observed in all known young, shell-type supernova
remnants (SNRs) in our Galaxy, including Cas A, Tycho, Kepler, and SN1006 and
yet the nature of these radial fields has not been thoroughly explored. Using a
3D model, we consider the existence and observational implications of an
intrinsically radial field. We also present a new explanation of the origin of
the radial pattern observed from polarization data as resulting from a
selection effect due to the distribution of cosmic-ray electrons (CREs). We
show that quasi-parallel acceleration can concentrate CREs at regions where the
magnetic field is radial, making a completely turbulent field appear ordered,
when it is in fact disordered. We discuss observational properties that may
help distinguish between an intrinsically radial magnetic field and the case
where it only appears radial due to the CRE distribution. We also show that the
case of an intrinsically radial field with a quasi-perpendicular CRE
acceleration mechanism has intriguing similarities to the observed polarization
properties of SN1006.
