Volume 613, May 2018
|Number of page(s)||4|
|Section||Letters to the Editor|
|Published online||23 May 2018|
Letter to the Editor
Excitation of vertical coronal loop oscillations by impulsively driven flows
Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick,
CV4 7AL, UK
Accepted: 23 April 2018
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−1 are sufficient to excite oscillations with observable amplitudes. We therefore propose plasma flows as a possible excitation mechanism for observed transverse loop oscillations.
Key words: magnetohydrodynamics / Sun: corona / Sun: oscillations / Sun: magnetic fields
© ESO 2018
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.