Speaker
Description
First Name: Antoine
Last Name: Dolliou
Email Address: dolliou@mps.mpg.de
Affiliation: MPS
All Authors: H. Peter, S. Mandal, P. Chitta, L. Teriaca, Y. Chen, D. Calchetti
Abstract: Network loops are a common feature in the quiet Sun, and the processes sustaining their energy budget are still not fully understood. In this work, our aim is to find signatures of the heating processes at the smallest scales, from the photospheric magnetic footpoints of the loop to its EUV emission in the coronal part. We relied on a multi-instrumental (Solar Orbiter/EUI, Solar Orbiter/PHI, IRIS) six-hour long observation of a quiet Sun region to investigate small-scale impulsive EUV emission enhancements with EUI/HRIEUV in three network loops. We measured periodicities between two to four minutes on the coronal part of the loop. In six of the events, plane of sky velocities on EUV perturbations showed fast (> 200 km/s) components; and two of them had a co-temporal slower component (< 80 km/s). In one case, we found that the slower component was associated with plasma motions, as evident from a Doppler shift of -30 km/s in the Si IV line. Signatures of bi-directional flows could also be found in the Si IV line along with the PoS velocities measured in HRIEUV images. Finally, we found evidence of small-scale (8E16 Mx) mixed polarity field emergence and fluctuation near one of the loop footpoints. We concluded that the fast components on the plane-of-sky are consistent with a thermal transfer or plasma flows, while the slower component is consistent with plasma flows. Our observational results shed new light on the driving of these small network loops. In particular, these observations suggest that the physical origin for these network loop brightenings might be found in periodic magnetic reconnection driven by either photospheric motions of the loop footpoints or the reconnection of the loop with other small-scale magnetic bipoles.