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Abstract: Transverse oscillations of small amplitude are commonly seen inhigh-resolution observations of filament threads, i.e. the fine-structures ofsolar filaments-prominences, and are typically damped in a few periods. Kinkwave modes supported by the thread body offer a consistent explanation of theseobserved oscillations. Among the proposed mechanisms to explain the kink modedamping, resonant absorption in the Alfven continuum seems to be the mostefficient as it produces damping times of about 3 periods. However, for anonzero-beta plasma and typical prominence conditions, the kink mode is alsoresonantly coupled to slow or cusp continuum modes, which could furtherreduce the damping time. In this Letter, we explore for the first time bothanalytically and numerically the effect of the slow continuum on the damping oftransverse thread oscillations. The thread model is composed of a homogeneousand straight cylindrical plasma, an inhomogeneous transitional layer, and thehomogeneous coronal plasma. We find that the damping of the kink mode due tothe slow resonance is much less efficient than that due to the Alfvenresonance.



Author: R. Soler, R. Oliver, J. L. Ballester, M. Goossens

Source: https://arxiv.org/



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