Polarized forbidden coronal line emission in the presence of active regions

Photoexcited forbidden lines at visible and infrared wavelengths provide important diagnostics for the coronal magnetic field via scattering induced polarization and the Zeeman Effect. In forward models, the polarized formation of these lines is often treated assuming a simplified exciting radiation field, consisting only of the photospheric quiet-sun continuum, which is both cylindrically-symmetric relative to the solar vertical and unpolarized. Near active regions in particular, this assumption breaks down, especially due to the presence of sunspots and other surface features that lead to additional asymmetries in the continuum radiation field. Here we investigate the role of symmetry-breaking on the emergent polarized emission within high resolution models of the active corona simulated by the MURaM code. We treat the full 3D (unpolarized) continuum radiation field of the photosphere exciting the coronal ions and compare the cases that include and ignore the symmetry-breaking effects of the photospheric features. Our discussion focuses on the key observables soon to be made available by the National Science Foundation's Daniel K Inouye Solar Telescope. The results indicate that while symmetry breaking can in principle have a large effect, its role is relatively minor for the simulated active region largely due to the low inherent polarization fraction emitted by forbidden lines in denser active region plasmas.