文章基本信息

标题：Excitation of vertical coronal loop oscillations by impulsively driven flows
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作者：P. Kohutova ; E. Verwichte
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2018
卷号：613
DOI：10.1051/0004-6361/201832656
语种：English
出版社：EDP Sciences
摘要：Context.Flows of plasma along a coronal loop caused by the pressure difference between loop footpoints are common in the solar corona.Aims.We aim to investigate the possibility of excitation of loop oscillations by an impulsively driven flow triggered by an enhanced pressure in one of the loop footpoints.Methods.We carry out 2.5D magnetohydrodynamic (MHD) simulations of a coronal loop with an impulsively driven flow and investigate the properties and evolution of the resulting oscillatory motion of the loop.Results.The action of the centrifugal force associated with plasma moving at high speeds along the curved axis of the loop is found to excite the fundamental harmonic of a vertically polarised kink mode. We analyse the dependence of the resulting oscillations on the speed and kinetic energy of the flow.Conclusions.We find that flows with realistic speeds of less than 100 km s−1are sufficient to excite oscillations with observable amplitudes. We therefore propose plasma flows as a possible excitation mechanism for observed transverse loop oscillations.
关键词：Key wordsenmagnetohydrodynamicsSun: coronaSun: oscillationsSun: magnetic fields