Simulating the solar corona in the forbidden and permitted lines with forward modeling. I. Saturated and unsaturated Hanle regimes

Linear polarization measurements in forbidden lines in the visible/IR provide information about coronal magnetic direction and topology. However, these measurements do not provide a constraint on coronal magnetic field strength.

The unsaturated, or critical regime of the magnetic Hanle effect is potentially observable in permitted lines for example in the UV, and would provide an important new constraint on the coronal magnetic field. In this paper we present the first side-by-side comparison of forbidden versus permitted linear polarization signatures, examining the transition from the unsaturated to the saturated regime. In addition, we use an analytic 3D flux rope model to demonstrate the Hanle effect for the line-of-sight versus plane-of-sky (POS) components of the magnetic field.