Abstracts submitted by Rui Pinto
Coronal seismology: wave leakage at the lower layers
R. Pinto, R. Grappin and J. Léorat
LUTh - Observatoire de Paris
Observed coronal loop oscillations are often interpreted as standing kink modes of magnetic flux tubes with both footpoints line-tied to the photosphere. These have been observed to decay very fast (approx. 1-3 wave periods; Nakariakov et al. 1999, Aschwanden et al. 2002), much too fast for the expected viscous damping. Alternative damping mechanisms were proposed, such as dissipation by phase mixing and/or resonant absorption at the flux tube's lateral boundaries, but were unsuccessful at reproducing the correct damping times. It's relevant, however, to consider propagative (rather than standing) modes and the possibility of footpoint leakage (Ofman 2002, del Zanna et al. 2005).
We perform 2.5D MHD numerical simulations of the response of coronal loops to localized perturbations in a domain including a realistic (and consistently maintained) transition region. |
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