Paper detail

Evolution of Stokes V area asymmetry related to a quiet Sun cancelation observed with GRIS/IFU

A quiet Sun magnetic flux cancelation event at the disk centre was recorded using the Integral Field Unit (IFU) mounted on the GREGOR Infrared Spectrograph (GRIS). GRIS sampled the event in the photospheric Si I 10827 Å spectral line. The cancelation is preceded by a significant rise in line core intensity and excitation temperature, which is inferred from Stokes inversions under local thermodynamic equilibrium (LTE). The opposite polarity features seem to undergo reconnection above the photosphere. We also found that the border pixels neighboring the polarity inversion line of one of the polarities exhibit a systematic variation of area asymmetry. Area asymmetry peaks right after the line core intensity enhancement and gradually declines thereafter. Analyzing Stokes profiles recorded from either side of the polarity inversion line could therefore potentially provide additional information on the reconnection process related to magnetic flux cancelation. Further analysis without assuming LTE will be required to fully characterize this event.