Abstract:
Angle-frequency coupling in scattering of polarized light on atoms is represented by the angle-dependent (AD)
partial frequency redistribution (PRD) matrices. There are several lines in the linearly polarized solar spectrum, for
which PRD combined with quantum interference between hyperfine structure states play a significant role. Here we
present the solution of the polarized line transfer equation including the AD-PRD matrix for scattering on a twolevel atom with hyperfine structure splitting and an unpolarized lower level. We account for the effects of arbitrary
magnetic fields (including the incomplete Paschen–Back effect regime) and elastic collisions. For exploratory
purposes we consider a self-emitting isothermal planar atmosphere and use atomic parameters that represent an
isolated Na I D2 line. For this case we show that the AD-PRD effects are significant for field strengths below about
30 G, but that the computationally much less demanding approximation of angle-averaged PRD may be used for
stronger fields.
