  The canonical theory of star formation in a magnetized environment predicts
the formation of hourglass-shaped magnetic fields during the prestellar
collapse phase. In protostellar cores, recent observations reveal complex and
strongly distorted magnetic fields in the inner regions that are sculpted by
rotation and outflows. We conduct resistive, nonideal magnetohydrodynamic (MHD)
simulations of a protostellar core and employ the radiative transfer code
POLARIS to produce synthetic polarization segment maps. Comparison of our
mock-polarization maps based on the toroidal-dominated magnetic field in the
outflow zone with the observed polarization vectors of SiO lines in Orion
Source I shows a reasonable agreement when the magnetic axis is tilted at an
angle $\theta = 15^{\circ}$ with respect to the plane-of-sky and if the SiO
lines have a net polarization parallel to the local magnetic field. Although
the observed polarization is from SiO lines and our synthetic maps are due to
polarized dust emission, a comparison is useful and allows us to resolve the
ambiguity of whether the line polarization is parallel or perpendicular to the
local magnetic field direction.
