EUV flickering of solar coronal loops: a new diagnostic of coronal heating

TL;DR

This study extends previous models of solar coronal loops by including spatially resolved strand modeling, revealing how EUV flickering varies along loops and offering a new diagnostic tool for nano-flaring regions.

Contribution

It introduces spatially resolved modeling of coronal loop emission and demonstrates how fluctuation amplitudes vary along loops, enhancing understanding of coronal heating mechanisms.

Findings

Fluctuation amplitude increases from bottom to top in 94 A channel.

Fluctuation amplitude increases from top to bottom in 335 A channel.

Pixel fluctuation maps can diagnose nano-flaring regions.

Abstract

A previous work of ours found the best agreement between EUV light curves observed in an active region core (with evidence of super-hot plasma) and those predicted from a model with a random combination of many pulse-heated strands with a power-law energy distribution. We extend that work by including spatially resolved strand modeling and by studying the evolution of emission along the loops in the EUV 94 A and 335 A channels of the Atmospheric Imaging Assembly on-board the Solar Dynamics Observatory. Using the best parameters of the previous work as the input of the present one, we find that the amplitude of the random fluctuations driven by the random heat pulses increases from the bottom to the top of the loop in the 94 A channel and, viceversa, from the top to the bottom in the 335 A channel. This prediction is confirmed by the observation of a set of aligned neighbouring pixels along a bright arc of an active region core. Maps of pixel fluctuations may therefore provide easy diagnostics of nano-flaring regions.