Anomalous Cooling of Coronal Loops with Turbulent Suppression of Thermal Conduction

TL;DR

This paper explores how turbulent suppression of thermal conduction affects the cooling of post-flare coronal loops, revealing that turbulence can significantly reduce conduction's role in cooling.

Contribution

It introduces a model for coronal loop cooling considering turbulent suppression and constrains turbulent parameters based on observed cooling times.

Findings

Turbulent suppression can limit thermal conduction in coronal loops.

Different cooling scenarios depend on the turbulent mean free path.

Turbulence can dominate cooling, reducing the role of collisions.

Abstract

We investigate the impact of turbulent suppression of parallel heat conduction on the cooling of post-flare coronal loops. Depending on the value of the mean free path $\lambda_T$ associated with the turbulent scattering process, we identify four main cooling scenarios. The overall temperature evolution, from an initial temperature in excess of $10^7$~K, is modeled in each case, highlighting the evolution of the dominant cooling mechanism throughout the cooling process. Comparison with observed cooling times allows the value of $\lambda_T$ to be constrained, and interestingly this range corresponds to situations where collision-dominated conduction plays a very limited role, or even no role at all, in the cooling of post-flare coronal loops.