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Small-scale, Dynamic Bright Blobs in Solar Filaments and Active Regions  

Yong Lin   Submitted: 2012-01-05 15:16

This abstract was corrupted following database problems and is being recovered. It will be restored as quickly as possible. Any questions, please send them to Alisdair. Sorry for any incovenience.


Authors: Y. Lin, O. Engvold and L.H.M. Rouppe van der Voort
Projects: None

Publication Status: ApJ, Vol. 746, February 2012, in press
Last Modified: 2012-01-09 07:29
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Filament Thread-like Structures and Their Small-amplitude Oscillations  

Yong Lin   Submitted: 2011-02-23 05:19

Thanks to gradually improving observational capabilities, both from space and ground-based observatories, it is now generally accepted that thin threads (width ∼200 km) constitute the building blocks of solar filaments and prominences. At ultra-small scales, high quality image sequences show a non-static picture of filaments and reveal that their oscillatory behavior is an important dynamic feature of these structures. Filament seismology sheds light on the internal magnetic structures of filaments and their interactions with surrounding solar regions. Understanding the overall magnetic topology of solar filaments and prominences including their small-scale thread-like structures is essential in interpretation and understanding of their oscillations. For this reason we aim here to present an update of the dynamic and spatial structures of prominences and filaments as inferred from high resolution observations in the past decennia. Some constraints in high resolution observations are addressed. Our review focuses mainly on the observational aspects and aims to summarize recent oscillation studies of individual filament threads and groups of threads. Finally, some theoretical interpretations of oscillations of filament threads and the inferred physical conditions of filament plasma are also discussed.

Authors: Lin, Yong
Projects: None

Publication Status: Space Sci. Rev. (2010 Nov)
Last Modified: 2011-02-23 09:39
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Subject will be restored when possible  

Yong Lin   Submitted: 2008-04-01 08:01

The main structural components of solar filaments, their spines, barbs, and legs at the extreme ends of the spine, are illustrated from recent high-resolution observations. The thread-like structures appear to be present in filaments everywhere and at all times. They are the fundamental elements of solar filaments. The interrelation of the spines, barbs and legs are discussed. From observations, we present a conceptual model of the magnetic field of a filament. We suggest that only a single physical model is needed to explain filaments in a continuous spectrum represented by active region filaments at one end and quiescent filaments at the other end.

Authors: Y. Lin, S.F. Martin, and O. Engvold
Projects: None

Publication Status: published in ASP Conference Series, 2008, Vol. 383, 235-242
Last Modified: 2008-09-23 21:11
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On small active region filaments, fibrils and surges  

Yong Lin   Submitted: 2007-08-01 06:07

High resolution Hα images and magnetograms (0.2 arcsec) of an active region were obtained in alternating time series at 42 s cadences using the Swedish 1-m Solar Telescope on 2004 August 21. The Hα filtergrams reveal an active region filament and surges consisting of thread-like structures which have widths similar to the widths of chromospheric fibrils, both recorded down to the resolution limit in the best images. All observed structures in the active region appear highly dynamic. Fibrils show counterstreaming strongly resembling the counterstreaming threads in filaments. Streaming, along the threads of surges extending more than 10 arcsec, is higher in speed (~ 20 km s-1) than in the filament and fibrils and appears to flow independently over and above the chromospheric fibrils. Blue shifts seen in the Hα Dopplergrams confirm the outward mass motion of the surges. However, in at least one case, we also see simultaneous downflows from the same site but in the opposite direction and downward toward the chromosphere. We suggest that the site between these two outward and downward flows identifies the place where magnetic reconnection could occur and thereby cause of the surge. This appears to imply that the reconnection site is in the high chromosphere or low corona.

Authors: Y. Lin, S.F. Martin, O. Engvold, L.H.M. Rouppe van der Voort, M. van Noort
Projects: None

Publication Status: J. Adv. Space Res., 2007 (in press)
Last Modified: 2007-08-01 09:22
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Evidence of Traveling Waves in Filament Threads  

Yong Lin   Submitted: 2007-06-07 03:00

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 km s-1) waves propagating along a number of threads with an average phase velocity of 12 km s-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 D?az 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.

Authors: Y. Lin, O. Engvold, L.H.M. Rouppe van der Voort, M. van Noort
Projects:

Publication Status: Solar Physics (in press)
Last Modified: 2007-08-01 05:45
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Abstracts by Author
Small-scale, Dynamic Bright Blobs in Solar Filaments and Active Regions
Filament Thread-like Structures and Their Small-amplitude Oscillations
Subject will be restored when possible
On small active region filaments, fibrils and surges
Evidence of Traveling Waves in Filament Threads

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