Evidence of Traveling Waves in Filament Threads

• Published in: Solar physics 2007-11, Vol.246 (1), p.65-72
• Main Authors: Lin, Y., Engvold, O., Rouppe van der Voort, L. H. M., van Noort, M.
• Format: Article
• Language: English
• Subjects: Solar physics; Studies; Waves
• ISSN: 0038-0938; 1573-093X
• DOI: 10.1007/s11207-007-0402-8

Issue Title: MHD Waves and Oscillations in Solar Magnetic Structures / Guest Editor: R. Erdélyi High-resolution Hα filtergrams (0.2'') obtained with the Swedish 1-m Solar Telescope resolve numerous very thin, thread-like structures in solar filaments. The threads are believed to represent thin magnetic flux tubes that must be longer than the observable threads. We report on evidence for small-amplitude (1-2 kms^sup -1^) waves propagating along a number of threads with an average phase velocity of 12 kms^sup -1^ and a wavelength of 4''. The oscillatory period of individual threads vary from 3 to 9 minutes. Temporal variation of the Doppler velocities averaged over a small area containing a number of individual threads shows a short-period (3.6 minutes) wave pattern. These short-period oscillations could possibly represent fast modes in accordance with numerical fibril models proposed by Díaz et al. (Astron. Astrophys. 379, 1083, 2001). In some cases, it is clear that the propagating waves are moving in the same direction as the mass flows. [PUBLICATION ABSTRACT]