APJ: Why and how are entire hydromagnetic structures only intermittently loaded with bright coronal plasma in the Sun? The present work scrutinizes more chromospheric and coronal data, with the aim of finding reproducible observational constraints on coronal heating mechanisms. Six independent scans of chromospheric active region magnetic fields are investigated and correlated to overlying hot plasma loops. For the first time, the footpoints of over 30 bright plasma loops are thus related to scalar proxies for the Poynting fluxes measured from the upper chromosphere. Although imperfect, the proxies all indicate a general lack of correlation between footpoint Poynting flux and loop brightness. Our findings consolidate the claim that unobserved physical processes are at work which govern the heating of long-lived coronal loops.
Footpoints of the solar coronal emission (red) do not correlate either with line of sight magnetic fields in the chromosphere (top) or with the estimate of electromagnetic energy emerging from the chromosphere (bottom panel). Data from SDO and DKIST are shown.