Bayesian evidence for two slow-wave damping models in hot coronal loops

TL;DR

This study uses Bayesian analysis to compare two models explaining slow-wave damping in hot coronal loops, finding evidence that thermal misbalance often plays a significant role, which could shed light on coronal heating processes.

Contribution

It introduces a Bayesian evidence-based approach to distinguish between damping models, highlighting the importance of thermal misbalance in coronal loop dynamics.

Findings

Evidence favors the thermal misbalance model in most cases.

Some loops are better explained by thermal conduction alone.

Results suggest different damping regimes may exist in coronal loops.

Abstract

We compute the evidence in favour of two models, one based on field-aligned thermal conduction alone and another that includes thermal misbalance as well, in explaining the damping of slow magneto-acoustic waves in hot coronal loops. Our analysis is based on the computation of the marginal likelihood and the Bayes factor for the two damping models. We quantify their merit in explaining the apparent relationship between slow mode periods and damping times, measured with SOHO/SUMER in a set of hot coronal loops. The results indicate evidence in favour of the model with thermal misbalance in the majority of the sample, with a small population of loops for which thermal conduction alone is more plausible. The apparent possibility of two different regimes of slow-wave damping, if due to differences between the loops of host active regions and/or the photospheric dynamics, may help with revealing the coronal heating mechanism.