2008/02/05 by J. Terradas, I. Arregui, R. Oliver +4 · 7 citations
Physics and Astronomy · #Absorption (acoustics) #Atomic physics #Attenuation #Computational physics #Coronal loop #Coupling (piping) #Excited state #Ionosphere and magnetosphere dynamics #Loop (graph theory) #Magnetohydrodynamic drive #Magnetohydrodynamics #Materials science #Mechanics #Optics #Physics #Plasma #Quantum mechanics #Solar and Space Plasma Dynamics #Solar wind #Stellar, planetary, and galactic studies #Transverse plane #astro-ph
paper · pdf · doi:10.1086/586733
arxiv created 2008/02/05 · openalex publication_date 2008/05/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study the excitation and damping of transverse oscillations in a multistranded model of a straight line-tied coronal loop. The transverse geometry of our equilibrium configuration is quite irregular and more realistic than the usual cylindrical loop model. By numerically solving the time-dependent ideal magnetohydrodynamic equations in two dimensions, we show how the global motion of the whole bundle of strands, excited by an external disturbance, is converted into localized Alfvénic motions due to the process of resonant absorption. This process produces the attenuation of the transverse oscillations. At any location in the structure, two dominant frequencies are found: the frequency of the global mode or quasi-mode, and the local Alfvén frequency. We find that the mechanism of mode conversion, due to the coupling between fast and Alfvén waves, is not compromised by the complicated geometry of the model. We also show that it is possible to have energy conversion not only at the external edge of the composite loop, but also inside the structure. The implications of these results and their relationship with the observations are discussed.