On the intermittency of hot plasma loops in the solar corona

TL;DR

This study investigates the relationship between magnetic flux proxies and plasma loop brightness in the solar corona, finding no strong correlation and suggesting unobserved processes influence coronal heating.

Contribution

It provides the first observational correlation between chromospheric magnetic proxies and coronal loop brightness, highlighting the role of unobserved heating mechanisms.

Findings

No strong correlation between Poynting flux proxies and loop brightness.

Evidence supporting the existence of unobserved physical processes in coronal heating.

Analysis of over 30 bright plasma loops across multiple datasets.

Abstract

A recent analysis has suggested that the heating of plasma loops in the solar corona depends not just on the Poynting flux but also on processes yet to be identified. This discovery reflects and refines earlier questions such as, why and how are entire hydromagnetic structures only intermittently loaded with bright coronal plasma Litwin & Rosner (1993)? 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.