The key role of solar dynamics in the chromospheric Hanle polarization
| Autor: | E. S. Carlin, M. Bianda |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Physics
Hanle effect Zeeman effect 010504 meteorology & atmospheric sciences Scattering Linear polarization FOS: Physical sciences Astronomy and Astrophysics Polarization (waves) Solar physics 01 natural sciences Electromagnetic radiation Computational physics symbols.namesake Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science 0103 physical sciences symbols Astrophysics::Solar and Stellar Astrophysics 010303 astronomy & astrophysics Chromosphere Solar and Stellar Astrophysics (astro-ph.SR) 0105 earth and related environmental sciences |
| Zdroj: | The Astrophysical Journal Letters |
| Popis: | The quantum theory of polarized light allows one to model scattering in the solar atmosphere for inferring its properties. This powerful approach has revealed two key long-standing problems in solar physics: the puzzling dilemmas between theory and observations in several anomalously polarized spectral lines and the need for inferring the ubiquitous weak chromospheric magnetic fields, which requires discriminating the Hanle effect in dynamic optically thick plasmas. However, the ever-present dynamics, i.e., the temporal evolution of heatings and macroscopic motions, has been widely disregarded when modeling and interpreting the scattering polarization. This has hindered a consistent theoretical solution to the puzzle while falsifying the Hanle diagnosis. Here, we show that the dynamical evolution is a keystone for solving both problems because its systematic impact allows an explanation of the observations from 'anomalous' instantaneous polarization signals. Evolution accounted for, we reproduce amplitudes and (spectral and spatial) shapes of the Ca I 4227 A polarization at solar disk center, identifying a restrictive arrangement of magnetic fields, kinematics, heatings, and spatio-temporal resolution. We find that the joint action of dynamics, Hanle effect, and low temporal resolutions mimics Zeeman linear polarization profiles, the true weak-field Zeeman signals being negligible. Our results allow reinterpretation of many polarization signals of the solar spectra and support time-dependent scattering polarization as a powerful tool for deciphering the spatio-temporal distribution of chromospheric heatings and fields. This approach may be a key aid in developing the Hanle diagnosis for the solar atmosphere. 5 pages, 4 figures, published in ApJL |
| Databáze: | OpenAIRE |
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