Solving the paradox of the solar sodium D1 line polarization

Abstract

Twenty-five years ago, enigmatic linear polarization signals were discovered in the core of the sodium D1 line. The only explanation that could be found implied that the solar chromosphere is practically unmagnetized, in contradiction with other evidences. This opened a paradox that has challenged physicists for many years. Here we present its solution, demonstrating that these polarization signals can be properly explained in the presence of magnetic fields in the gauss range. This result opens a novel diagnostic window for exploring the elusive magnetism of the solar chromosphere.

Main article has a length of 5 pages and contains 2 figures. Supplemental Material has a length of 6 pages and contains 3 figures. Note that the main article and the Supplemental Material have separate reference lists. Article published in open access by Physical Review Letters on 18/08/2021; Link: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.127.081101

References in corpus (5)

• Magnetic Diagnostics of the Solar Chromosphere with the Mg II h-k Lines
• The magnetic sensitivity of the Mg ii k line to the joint action of Hanle, Zeeman and magneto-optical effects
• The Hanle and Zeeman polarization signals of the solar Ca II 8542 Å line
• Master equation theory applied to the redistribution of polarized radiation in the weak radiation field limit. V. The two-term atom
• Physics of polarized scattering at multi-level atomic systems

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• The European Solar Telescope
• Center-to-limb variation of spectral lines and continua observed with SST/CRISP and SST/CHROMIS
• Modeling the scattering polarization of the solar Ca i 4227 Å line with angle-dependent partial frequency redistribution
• The transfer of polarized radiation in resonance lines with partial frequency redistribution, J-state interference, and arbitrary magnetic fields. A radiative transfer code and useful approximations
• Hanle rotation signatures in Sr I 4607 Å
• Assessment of the CRD approximation for the observer's frame RIII redistribution matrix
• A numerical approach for modelling the polarisation signals of strong resonance lines with partial frequency redistribution. Numerical applications to two-term atoms and plane-parallel atmospheres
• Diagnostic potential of wavelength-integrated scattering polarisation signals of the solar He II Ly-alpha line
• On the center-to-limb variations of the He I 10 830 Å triplet
• Collisional effects in modeling solar polarized lines