Below is a beautiful image of a so called coronal loop system on the Sun as seen by the ultra violet cameras on the Solar Dynamics Observatory. The image covers 50,000 miles of the Sun's surface and can be seen, again, at https://phys.org/news/2019-09-solar-corona.html …
… the Interface Region Imaging Spectrograph measured short lived brightenings in the loop which enabled astronomers to identify for the first time the possible importance of nonthermal electrons in the heating of non flaring but active coronal regions of the Sun – according to Reale et al 'Impulsive Coronal Heating from Large Scale Magnetic Re-arrangements: from IRIS to SDO/AIA' which can be found in the Astrophysical Journal at https://doi.org/10.3847/1538-4357/ab304f