Speaker
Description
First Name: Nicolas
Last Name: Le Nestour
Affiliation: LPC2E
All Authors: Le Nestour, N. ; Froment, C. ; Downs, C. ; Poirier, N., ; Auchère, F.; Masson, S.
Abstract: Thermal non-equilibrium (TNE) is a common feature of active-region loops. TNE consists of cyclic plasma evaporation and condensation driven by a highly stratified and quasi-steady heating. Long-period (several-hours) EUV pulsations and coronal rain are two signatures of these periodic variations in coronal temperature and density. However, the bias of current Fourier-based detections toward ideal cases hinders accurate evaluation of the coronal volume undergoing TNE cycles, a key parameter for coronal heating models. Based on a 3D hydrodynamic simulation (MAS) and synthetic observations of AR 11139, we aim to determine: (1) the fraction of the active-region volume subject to TNE cycles, and (2) the proportion of these cycles that can be detected in synthetic EUV observations. To address these questions, we adapt the method of Auchère et al. 2014 in order to detect 3D temperature and density periodicities. We identify regions exhibiting TNE in the volume of the active region and compare them with those of long-period EUV pulsations. A significant part of the AR volume (at least one third) undergoes TNE cycles, mostly in coronal loops. However, not all the cycles are detected in the synthetic observations, especially when there are multiple TNE cycles along the line-of-sight. We conclude that the current observational studies may greatly underestimate the volume occupied by TNE. We additionally detect TNE in open magnetic structures. This finding reinforces the hypothesis of Scott et al. (2024) that TNE can develop in open field regions and may inject material periodically into the solar wind.