Non-Potential Fields In The Quiet Sun Network: Extreme-Ultraviolet And Magnetic Footpoint Observations
The Astrophysical Journal Letters
The quiet Sun (QS) magnetic network is known to contain dynamics which are indicative of non-potential ﬁelds. Non-potential magnetic ﬁelds forming “S-shaped” loop arcades can lead to the breakdown of static activity and have only been observed in high temperature X-ray coronal structures—some of which show eruptive behavior. Thus, analysis of this type of atmospheric structuring has been restricted to large-scale coronal ﬁelds. Here we provide the ﬁrst identiﬁcation of non-potential loop arcades exclusive to the QS supergranulation network. High-resolution Atmospheric Imaging Assembly data from the Solar Dynamics Observatory have allowed for the ﬁrst observations of ﬁne-scale “S-shaped” loop arcades spanning the network. We have investigated the magnetic footpoint ﬂux evolution of these arcades from Heliospheric and Magnetic Imager data and ﬁnd evidence of evolving footpoint ﬂux imbalances accompanying the formation of these non-potential ﬁelds. The existence of such non-potentiality conﬁrms that magnetic ﬁeld dynamics leading to the build up of helicity exist at small scales. QS non-potentiality also suggests a self-similar formation process between the QS network and high temperature corona and the existence of self-organized criticality (SOC) in the form of loop-pair reconnection and helicity dissipation. We argue that this type of behavior could lead to eruptive forms of SOC as seen in active region (AR) and X-ray sigmoids if sufﬁcient free magnetic energy is available. QS magnetic network dynamics may be considered as a coronal proxy at supergranular scales, and events conﬁned to the network can even mimic those in coronal ARs.
Chesney, David L.; Oluseyi, Hakeem M.; and Orange, Norton B., "Non-Potential Fields In The Quiet Sun Network: Extreme-Ultraviolet And Magnetic Footpoint Observations" (2013). Aerospace, Physics, and Space Science Faculty Publications. 352.