文章基本信息

标题：Damping of nonlinear standing kink oscillations: a numerical study
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作者：N. Magyar ; N. Magyar ; T. Van Doorsselaere 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2016
卷号：595
页码：1-9
DOI：10.1051/0004-6361/201629010
语种：English
出版社：EDP Sciences
摘要：Aims. We aim to study the standing fundamental kink mode of coronal loops in the nonlinear regime, investigating the changes in energy evolution in the cross-section and oscillation amplitude of the loop which are related to nonlinear effects, in particular to the development of the Kelvin-Helmholtz instability (KHI). Methods. We run ideal, high-resolution three-dimensional (3D) magnetohydrodynamic (MHD) simulations, studying the influence of the initial velocity amplitude and the inhomogeneous layer thickness. We model the coronal loop as a straight, homogeneous magnetic flux tube with an outer inhomogeneous layer, embedded in a straight, homogeneous magnetic field. Results. We find that, for low amplitudes which do not allow for the KHI to develop during the simulated time, the damping time agrees with the theory of resonant absorption. However, for higher amplitudes, the presence of KHI around the oscillating loop can alter the loop’s evolution, resulting in a significantly faster damping than predicted by the linear theory in some cases. This questions the accuracy of seismological methods applied to observed damping profiles, based on linear theory.
关键词：Sun: corona;Sun: oscillations;magnetohydrodynamics (MHD)