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dc.contributor.authorAntolin, P.
dc.contributor.authorDe Moortel, Ineke
dc.contributor.authorVan Doorsselaere, T.
dc.contributor.authorYokoyama, T.
dc.identifier.citationAntolin , P , De Moortel , I , Van Doorsselaere , T & Yokoyama , T 2016 , ' Modeling observed decay-less oscillations as resonantly enhanced Kelvin-Helmholtz vortices from transverse MHD waves and their seismological application ' , Astrophysical Journal Letters , vol. 830 , no. 2 , L22 .
dc.identifier.otherPURE: 246364984
dc.identifier.otherPURE UUID: 4ef20e64-3cb8-4daa-a4ee-e49e9ded0844
dc.identifier.otherBibCode: 2016ApJ...830L..22A
dc.identifier.otherScopus: 84992753556
dc.identifier.otherBibCode: 2016ApJ...830L..22A
dc.identifier.otherORCID: /0000-0002-1452-9330/work/39526517
dc.identifier.otherWOS: 000401603200001
dc.description.abstractIn the highly structured solar corona, resonant absorption is an unavoidable mechanism of energy transfer from global transverse MHD waves to local azimuthal Alfvén waves. Due to its localised nature, a direct detection of this mechanism is extremely difficult. Yet, it is the leading theory explaining the observed fast damping of the global transverse waves. However, at odds with this theoretical prediction, recent observations indicate that in the low amplitude regime such transverse MHD waves can also appear decay-less, a yet unsolved phenomenon. Recent numerical work has shown that Kelvin-Helmholtz instabilities (KHI) often accompany transverse MHD waves. In this work, we combine 3D MHD simulations and forward modelling to show that for currently achieved spatial resolution and observed small amplitudes, an apparent decay-less oscillation is obtained. This effect results from the combination of periodic brightenings produced by the KHI and the coherent motion of the KHI vortices amplified by resonant absorption. Such effect is especially clear in emission lines forming at temperatures that capture the boundary dynamics rather than the core, and reflects the low damping character of the local azimuthal Alfvén waves resonantly coupled to the kink mode. Due to phase mixing, the detected period can vary depending on the emission line, with those sensitive to the boundary having shorter periods than those sensitive to the loop core. This allows to estimate the density contrast at the boundary.
dc.relation.ispartofAstrophysical Journal Lettersen
dc.rights© 2016, American Astronomical Society. This work is made available online in accordance with the publisher’s policies. This is the author created, accepted version manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at
dc.subjectMagnetohydrodynamic (MHD)en
dc.subjectSun: activityen
dc.subjectSun: coronaen
dc.subjectSun: oscillationsen
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.titleModeling observed decay-less oscillations as resonantly enhanced Kelvin-Helmholtz vortices from transverse MHD waves and their seismological applicationen
dc.typeJournal itemen
dc.contributor.institutionUniversity of St Andrews.Applied Mathematicsen
dc.contributor.institutionUniversity of St Andrews.School of Mathematics and Statisticsen
dc.description.statusPeer revieweden

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