Speaker
Description
We investigate small-scale magnetic features in the quiet solar photosphere through high-resolution multi-wavelength spectropolarimetric observations taken by the Sunrise Chromospheric Infrared spectro-Polarimeter on board the Sunrise-III stratospheric balloon-borne solar observatory. The instrument allows for high signal-to-noise observations of multiple spectral lines.
Our analysis focuses on Stokes $V$ profiles exhibiting a larger blue lobe. We detect asymmetries in such profiles across various spectral lines forming at different atmospheric heights, from the lower to the upper photosphere. The observations show that spectral lines formed in the higher photosphere, such as Fe I 8468 Å and K I 7698Å, exhibit strong line asymmetries. In contrast, the asymmetries are significantly weaker for lines formed in the lower photosphere, such as Fe I 8471 Å and Fe I 8526 Å.
By comparing spectral lines with different formation heights, we find that the degree of Stokes $V$ asymmetry tends to increase with formation height, and the magnetic polarity remains consistent across all analyzed lines, including the K I line and the chromospheric Ca II lines. In addition, the Stokes $V$ zero-crossing velocity measured directly from these profiles systematically decreases (i.e., becomes less blueshifted) with increasing formation height. This indicates that the overall upward line-of-sight velocity of the magnetic features is lower in the upper photosphere than in the lower layers.