Title of the publication
Publication: Astronomy & Astrophysics
1st Author: Rebecca A. Robinson
Position: Doctoral Research Fellow
Co-authors from RoCS:
- Mats Carlsson
- Guillaume Aulanier
Short summary by the author:
We have identified a reconnection-driven coronal heating event in a quiet Sun simulation. We find that our results are in good phenomenological agreement with idealized coronal flare models, which demonstrates that the same general physical concepts are valid. However, we also find that the reconnecting flux rope and arcade are neither formed by any obvious coherent flux emergence, nor by any ordered photospheric motion or flux cancellation. Instead, they seem to develop merely from the self-consistent convective driving of pre-existing tangled field lines. This gradual and smooth ordering suggests an inverse cascade of magnetic helicity via smaller reconnection events, located at or above slowly-moving photospheric flux concentrations. We suggest that this case is representative of many heating events that may be ubiquitous in the real quiet Sun.
Title of the publication
The chromosphere underneath a Coronal Bright Point
Publication: Astrophysical Journal
1st Author: Souvik Bose
Position: Affiliated researcher
Co-authors from RoCS:
- Daniel Nóbrega-Siverio
- Bart De Pontieu
- Luc Rouppe van der Voort
Short summary by the author:
Coronal Bright Points (CBPs) are sets of small-scale coronal loops, connecting opposite magnetic polarities, primarily characterized by their enhanced extreme-ultraviolet (EUV) and X-ray emission. Being ubiquitous, they are thought to play an important role in heating the solar corona. We aim at characterizing the barely-explored chromosphere underneath CBPs, focusing on the related spicular activity and on the effects of small-scale magnetic flux emergence on CBPs. We used high-resolution observations of a CBP in Hβ and Fe I 617.3 nm from the Swedish 1-m Solar Telescope (SST) in coordination with the Solar Dynamics Observatory (SDO). This work presents the first high-resolution observation of spicules imaged in Hβ. The spicules were automatically detected using advanced image processing techniques, which were applied to the Dopplergrams derived from Hβ. Here we report their abundant occurrence close to the CBP ``footpoints", and find that the orientation of such spicules is aligned along the EUV loops, indicating that they constitute a fundamental part of the whole CBP magnetic structure. Spatio-temporal analysis across multiple channels indicates that there are coronal propagating disturbances associated with the studied spicules, producing transient EUV intensity variations of the individual CBP loops. Two small-scale flux emergence episodes appearing below the CBP were analyzed; one of them leading to quiet-sun Ellerman bombs and enhancing the nearby spicular activity. This paper presents unique evidence of the tight coupling between the lower and upper atmosphere of a CBP, thus helping to unravel the dynamic phenomena underneath CBPs and their impact on the latter.