Temporal relation between quiet-Sun transverse fields and the strong flows detected by IMaX/SUNRISE

摘要

Localized strongly Doppler-shifted Stokes V signals were detected byIMaX/SUNRISE. These signals are related to newly emerged magnetic loops thatare observed as linear polarization features. We aim to set constraints on thephysical nature and causes of these highly Doppler-shifted signals. Inparticular, the temporal relation between the appearance of transverse fieldsand the strong Doppler shifts is analyzed in some detail. We calculated thetime difference between the appearance of the strong flows and the linearpolarization. We also obtained the distances from the center of variousfeatures to the nearest neutral lines and whether they overlap or not. Thesedistances were compared with those obtained from randomly distributed points onobserved magnetograms. Various cases of strong flows are described in somedetail. The linear polarization signals precede the appearance of the strongflows by on average 84+-11 seconds. The strongly Doppler-shifted signals arecloser (0.19") to magnetic neutral lines than randomly distributed points(0.5"). Eighty percent of the strongly Doppler-shifted signals are close to aneutral line that is located between the emerging field and pre-existingfields. That the remaining 20% do not show a close-by pre-existing field couldbe explained by a lack of sensitivity or an unfavorable geometry of thepre-existing field, for instance, a canopy-like structure. Transverse fieldsoccurred before the observation of the strong Doppler shifts. The process ismost naturally explained as the emergence of a granular-scale loop that firstgives rise to the linear polarization signals, interacts with pre-existingfields (generating new neutral line configurations), and produces the observedstrong flows. This explanation is indicative of frequent small-scalereconnection events in the quiet Sun.