Non-local thermal transport impact on compressive waves in two-temperature coronal loops

¹ Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL, UK
² Healthcare Technology Institute, School of Chemical Engineering, The University of Birmingham, Birmingham, UK
³ Engineering Research Institute “Ventspils International Radio Astronomy Centre (VIRAC)”, Ventspils University of Applied Sciences, Ventspils LV-3601, Latvia

^⋆ Corresponding author; Sergey.Belov@warwick.ac.uk

Received: 8 November 2024
Accepted: 7 December 2024

Abstract

Context. Observations of slow magnetoacoustic waves in solar coronal loops suggest that in hot coronal plasma, heat conduction may be suppressed in comparison with the classical thermal transport model.

Aims. We link this suppression with the effect of the non-local thermal transport that appears when the plasma temperature perturbation gradient becomes comparable to the electron mean-free-path. Moreover, we consider a finite time of thermalisation between electrons and ions so that separate electron and ion temperatures can occur in the loop.

Methods. We numerically compared the influence of the local and non-local thermal transport models on standing slow waves in one- and two-temperature coronal loops. To quantify our comparison, we used the period and damping time of the waves as commonly observed parameters.

Results. Our study reveals that non-local thermal transport can result in either shorter or longer slow-wave damping times in comparison with the local conduction model due to the suppression of the isothermal regime. The difference in damping times can reach 80%. For hot coronal loops, we find that the finite equilibration between electron and ion temperatures results in an up to 50% longer damping time compared to the one-temperature case. These results indicate that non-local transport will influence the dynamics of compressive waves across a broad range of coronal plasma parameters with Knudsen numbers (the ratio of mean-free-path to temperature scale length) larger than 1%.

Conclusions. In the solar corona, the non-local thermal transport shows a significant influence on the dynamics of standing slow waves in a broad range of plasma parameters, while two-temperature effects come into play for hot and less dense loops.