We analyze a confined flare that developed a hot cusp-like structure high in the corona (H ~ 66 Mm). A growing cusp-shaped flare arcade is a typical feature in the standard model of eruptive flares, caused by magnetic reconnection at progressively larger coronal heights. In contrast, we observe a static hot cusp during a confined flare. Despite an initial vertical temperature distribution similar to that in eruptive flares, we observe a distinctly different evolution during the late (decay) phase, in the form of prolonged hot emission. The distinct cusp shape, rooted at locations of non-thermal precursor activity, was likely caused by a magnetic field arcade that kinked near the top. Our observations indicate that the prolonged heating was a result of slow local reconnection and an increased thermal pressure near the kinked apexes due to continuous plasma upflows.
@article{arxiv.1911.10859,
title = {A Hot Cusp-Shaped Confined Solar Flare},
author = {Aaron Hernandez-Perez and Yang Su and Julia K. Thalmann and Astrid M. Veronig and Ewan C. Dickson and Karin Dissauer and Bhuwan Joshi and Ramesh Chandra},
journal= {arXiv preprint arXiv:1911.10859},
year = {2020}
}