Simulations of fully deformed oscillating flux tubes

Karampelas, Konstantinos and Van Doorsselaere, T. (2018) Simulations of fully deformed oscillating flux tubes. Astronomy & Astrophysics, 610. L9. ISSN 0004-6361

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Official URL: https://doi.org/10.1051/0004-6361/201731646

Abstract

Context. In recent years, a number of numerical studies have been focusing on the significance of the Kelvin–Helmholtz instability in the dynamics of oscillating coronal loops. This process enhances the transfer of energy into smaller scales, and has been connected with heating of coronal loops, when dissipation mechanisms, such as resistivity, are considered. However, the turbulent layer is expected near the outer regions of the loops. Therefore, the effects of wave heating are expected to be confined to the loop’s external layers, leaving their denser inner parts without a heating mechanism.

Aim. In the current work we aim to study the spatial evolution of wave heating effects from a footpoint driven standing kink wave in a coronal loop.

Methods. Using the MPI-AMRVAC code, we performed ideal, three dimensional magnetohydrodynamic simulations of footpoint driven transverse oscillations of a cold, straight coronal flux tube, embedded in a hotter environment. We have also constructed forward models for our simulation using the FoMo code.

Results. The developed transverse wave induced Kelvin–Helmholtz (TWIKH) rolls expand throughout the tube cross-section, and cover it entirely. This turbulence significantly alters the initial density profile, leading to a fully deformed cross section. As a consequence, the resistive and viscous heating rate both increase over the entire loop cross section. The resistive heating rate takes its maximum values near the footpoints, while the viscous heating rate at the apex.

Conclusions. We conclude that even a monoperiodic driver can spread wave heating over the whole loop cross section, potentially providing a heating source in the inner loop region. Despite the loop’s fully deformed structure, forward modelling still shows the structure appearing as a loop.

Item Type: Article
Additional Information: 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 the IAP P7/08 CHARM (Belspo) and the GOA-2015-014 (KU Leuven). 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 results were inspired by discussions at the ISSI-Bern and at ISSI-Beijing meetings.
Uncontrolled Keywords: magnetohydrodynamics (MHD), Sun: corona, Sun: oscillations
Subjects: F300 Physics
F500 Astronomy
Department: Faculties > Engineering and Environment > Mathematics, Physics and Electrical Engineering
Depositing User: Rachel Branson
Date Deposited: 05 Jul 2021 14:46
Last Modified: 05 Jul 2021 15:00
URI: http://nrl.northumbria.ac.uk/id/eprint/46607

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