Observation and modeling of scattering polarization signals sensitive to unresolved photospheric magnetic fields via Hanle and magneto-optical effects

Diplôme Thèse Observation and modeling of scattering polarization signals sensitive to unresolved photospheric magnetic fields via Hanle and magneto-optical effects eng 2021-06-18 author Capozzi Emilia 880096 director Meynet Georges 22422 director Bianda Michele 10.13097/archive-ouverte/unige:154699 urn:nbn:ch:unige-1546993 Sc. 5578 The main focus of this Thesis is to explore and apply techniques based on scattering polarization to study certain aspects of the solar magnetism that are not accessible through more widespread techniques. Using the ZIMPOL instrument at the GREGOR solar telescope, we measured the spatial variation of the scattering polarization signals of the Sr I 4607 Å line, whose sensitivity to Hanle effect encodes information on the small-scale magnetic fields present in the solar photosphere. Performing new observations using ZIMPOL at IRSOL and at GREGOR, we found clear observational proof that the scattering polarization wings of the chromospheric Ca I 4227 Å line are sensitive to photospheric magnetic fields via magneto-optical effects. We finally explored the diagnostic potential of such sensitivity by theoretically modeling the Ca I 4227 Å line and we identified the linear polarization angle as an observable of interest for diagnosing solar magnetic fields. Polarization Scattering Sun Chromosphere Photosphere Magnetic fields Dewey 520 26 Département d'astronomie 12 false 866 Direction de recherche "Physique stellaire" 867 Groupe Meynet 7d5934f6-89d8-4c88-9ccb-a96e2cc35434 Thesis Public PhDthesis_CapozziE.pdf 5686171 application/pdf openAccess Faculté des sciences / Département d'astronomie

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Observation and modeling of scattering polarization signals sensitive to unresolved photospheric magnetic fields via Hanle and magneto-optical effects				2021	465	233

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Capozzi, Emilia