On the polarimetric signature of emerging magnetic loops in the quiet sun

Abstract

The abundance of Stokes V profiles dominated by one lobe at the locations of emergence of Ω-shaped magnetic loops is evaluated. The emergence events were found in Hinode Solar Optical Telescope/spectro-polarimeter time sequences of quiet-Sun regions. Such a study has the aim of confirming a prediction based on the basic geometrical and physical properties of emerging magnetic loops: Stokes V profiles dominated by one lobe are possibly the main polarimetric signature of these structures. In agreement with this prediction, 47% of the Stokes V profiles analyzed have an amplitude asymmetry |δa| > 0.3, while in the quiet Sun the abundance is of about 30%. This excess with respect to the quiet Sun is found consistently for any value of the threshold on the amplitude asymmetry. Such a result proves the goodness of the physical scenarios so far proposed for the interpretation of loop emergence events and may prompt the use of Stokes V profiles dominated by one lobe as a new proxy for their identification in observations with a good spectral sampling. © 2012. The American Astronomical Society. All rights reserved.