Abstract:
Magnetic fields in the solar atmosphere leave their fingerprints in the polarized spectrum of the Sun via the Hanle
and Zeeman effects. While the Hanle and Zeeman effects dominate, respectively, in the weak and strong field
regimes, both these effects jointly operate in the intermediate field strength regime. Therefore, it is necessary to
solve the polarized line transfer equation, including the combined influence of Hanle and Zeeman effects.
Furthermore, it is required to take into account the effects of partial frequency redistribution (PRD) in scattering
when dealing with strong chromospheric lines with broad damping wings. In this paper, we present a numerical
method to solve the problem of polarized PRD line formation in magnetic fields of arbitrary strength and
orientation. This numerical method is based on the concept of operator perturbation. For our studies, we consider a
two-level atom model without hyperfine structure and lower-level polarization. We compare the PRD idealization
of angle-averaged Hanle–Zeeman redistribution matrices with the full treatment of angle-dependent PRD, to
indicate when the idealized treatment is inadequate and what kind of polarization effects are specific to angledependent PRD. Because the angle-dependent treatment is presently computationally prohibitive when applied to
realistic model atmospheres, we present the computed emergent Stokes profiles for a range of magnetic fields, with
the assumption of an isothermal one-dimensional medium.
