Physical basis of solar spectropolarimetry

Author: Egidio Landi degl’Innocenti
Affiliation: University of Florence


Solar spectropolarimetry was born more than a century ago when Hale observed the signature of the Zeeman effect in the spectrum of a sunspot, thus discovering the presence of a magnetic field on a cosmic object, the sun. Things have dramatically evolved since those times, both from the point of view of instrumentation and of the theoretical tools needed for the interpretation of the observations. However, notwithstanding the important results that have been obtained in this research field, we are still far from having a satisfactory understanding of the structure and morphology of the solar magnetic field, either in the photosphere or in its outer layers, the chromosphere and the corona.

In the present talk I will review the basic physical processes that are involved in the generation and transfer of polarized radiation in the solar atmosphere highlighting the progress that has been made in the past and the work that is still needed to reach a satisfactory diagnostics of the solar magnetic field through modern spectropolarimetric observations.