Hyperfine structure as a diagnostic of solar magnetic fields

We propose the use of the Zeeman effect of the hyperfine structure (HFS) as a diagnostic of solar photospheric magnetic fields. The HFS induces unique signatures in the polarized spectra of particular atoms, which can be used to directly get information on the magnetic field strength. To explore the effects of HFS, we adopt a numerical model of line formation and radiative transfer of polarized light in a magnetized Milne-Eddington atmosphere. We concentrate our studies on several lines of Mn I, which show particularly striking HFS signatures in the solar atlas. For these lines, anomalous Stokes profiles are produced for fields in the range 0-1000 G. The presence of these unusual profiles for weak magnetic fields constitutes a novel and potentially powerful diagnostic of the strength of solar magnetic fields in the quiet photosphere and plages.