Wave heating in gravitationally stratified coronal loops in the presence of resistivity and viscosity

Karampelas, Konstantinos, Van Doorsselaere, T. and Guo, M. (2019) Wave heating in gravitationally stratified coronal loops in the presence of resistivity and viscosity. Astronomy & Astrophysics, 623. A53. ISSN 0004-6361

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Official URL: https://doi.org/10.1051/0004-6361/201834309

Abstract

Context. In recent years, coronal loops have been the focus of studies related to the damping of different magnetohydrodynamic (MHD) surface waves and their connection with coronal seismology and wave heating. For a better understanding of wave heating, we need to take into account the effects of different dissipation coefficients such as resistivity and viscosity, the importance of the loop physical characteristics, and the ways gravity can factor into the evolution of these phenomena.

Aims. We aim to map the sites of energy dissipation from transverse waves in coronal loops in the presence and absence of gravitational stratification and to compare ideal, resistive, and viscous MHD.

Methods. Using the PLUTO code, we performed 3D MHD simulations of kink waves in single, straight, density-enhanced coronal flux tubes of multiple temperatures.

Results. We see the creation of spatially expanded Kelvin–Helmholtz eddies along the loop, which deform the initial monolithic loop profile. For the case of driven oscillations, the Kelvin–Helmholtz instability develops despite physical dissipation, unless very high values of shear viscosity are used. Energy dissipation gets its highest values near the apex, but is present all along the loop. We observe an increased efficiency of wave heating once the kinetic energy saturates at the later stages of the simulation and a turbulent density profile has developed.

Conclusions. The inclusion of gravity greatly alters the dynamic evolution of our systems and should not be ignored in future studies. Stronger physical dissipation leads to stronger wave heating in our set-ups. Finally, once the kinetic energy of the oscillating loop starts saturating, all the excess input energy turns into internal energy, resulting in more efficient wave heating.

Item Type: Article
Additional Information: Acknowledgements. We would like to thank the referee whose review helped us improve the manuscript. We also thank the editor for his comments. K.K. was funded by GOA-2015-014 (KU Leuven). T.V.D. was supported by GOA2015-014 (KU Leuven). M.G. is also supported by the National Natural Science Foundation of China (41674172). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 724326). The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Research Foundation Flanders (FWO) and the Flemish Government – department EWI. The results were inspired by discussions at the ISSI-Bern and at ISSI-Beijing meetings.
Uncontrolled Keywords: Sun: corona, Sun: oscillations, magnetohydrodynamics (MHD)
Subjects: F300 Physics
F500 Astronomy
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Rachel Branson
Date Deposited: 05 Jul 2021 14:52
Last Modified: 05 Jul 2021 15:00
URI: http://nrl.northumbria.ac.uk/id/eprint/46608

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