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EP: Fachverband Extraterrestrische Physik

EP 4: Sun and Heliosphere II

EP 4.3: Vortrag

Dienstag, 1. April 2025, 14:30–14:45, ZHG101

Stereoscopic disambiguation of solar vector magnetic fields using observations from SO/PHI and SDO/HMI — •Xiang Li, Gherardo Valori, Daniele Calchetti, Sami Solanki, Johann Hirzberger, and Jonas Sinjan — Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany

The solar vector magnetic field is inferred from spectropolarimetric observations of the polarization in magnetically sensitive spectral lines. However, the transverse component has a 180° ambiguity in its orientation. Traditional single-view methods for resolving the ambiguity require assumptions on the properties of the photospheric magnetic field. The Polarimetric and Helioseismic Imager (PHI) on board Solar Orbiter (SO) makes it possible to remove the ambiguity purely using observations from two vantage points. The Stereoscopic Disambiguation Method (SDM), which was developed based on this idea, has been successfully tested on simulated data and first science data acquired from the High Resolution Telescope (SO/PHI-HRT) in spring 2022. In this work, we applied the SDM to a number of SO/PHI-HRT datasets and corresponding datasets from the Helioseismic and Magnetic Imager (HMI) on board Solar Dynamics Observatory (SDO). The SDM successfully disambiguates the vector magnetograms in strong field areas, and for a large range of separation angles between the viewpoints. We analyzed quantitative diagnostic metrics on different observational configurations to explore factors that may affect the reliability of the SDM in localized areas. Furthermore, a possible improvement of SDM is proposed based on a detailed analysis of the SDM equations.

Keywords: Solar magnetic fields; Solar photosphere; Solar observations