Observations of Filament Structure and Dynamics

Engvold, O.

doi:10.1017/s0252921100047229

Cited by 6 publications

(7 citation statements)

References 29 publications

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“…The fine threads of solar filaments seem to be partially filled with cold plasma (Lin et al 2005), typically two orders of magnitude denser and cooler than the surrounding corona, and it is generally assumed that they outline the magnetic flux tubes in which they reside (Engvold 1998;Lin 2005;Lin et al 2005;Okamoto et al 2007;Engvold 2008;Martin et al 2008;). This idea is strongly supported by observations, which suggest that threads are skewed with respect to the filament long axis in a similar way to what has been found for the magnetic field (Leroy 1980;Bommier et al 1994;Bommier and Leroy 1998).…”

Section: Prominencesmentioning

confidence: 99%

Prominence oscillations

Arregui

Oliver

Ballester

2018

Living Rev Sol Phys

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Prominences are intriguing, but poorly understood, magnetic structures of the solar corona. The dynamics of solar prominences has been the subject of a large number of studies, and of particular interest is the study of prominence oscillations. Ground-and space-based observations have confirmed the presence of oscillatory motions in prominences and they have been interpreted in terms of magnetohydrodynamic waves. This interpretation opens the door to perform prominence seismology, whose main aim is to determine physical parameters in magnetic and plasma structures (prominences) that are difficult to measure by direct means. Here, we review the This article is a revised version of https://doi.org/10.12942/lrsp-2012-2. Change summary: Major revision, updated and expanded. Change details: New section on Bayesian analysis. New observations and theoretical models for small and for large amplitude oscillations. About 50 new references were added.

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Section: Prominencesmentioning

confidence: 99%

Prominence oscillations

Arregui

Oliver

Ballester

2018

Living Rev Sol Phys

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“…Intermediate filaments form between weak unipolar background field regions and active region complexes (Engvold 1998). The target filament that we selected was an intermediate filament which was located at a boundary between a decaying active region complex (AR10386 and AR10389) and the surrounding unipolar quiet region.…”

Section: Methodsmentioning

confidence: 99%

Magnetic Helicity Injection During the Formation of an Intermediate Filament

Jeong¹,

Chae²,

Moon³

2009

Journal of The Korean Astronomical Society

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A necessary condition for the formation of a filament is magnetic helicity. In the present paper we seek the origin of magnetic helicity of intermediate filaments. We observed the formation of a sinistral filament at the boundary of a decaying active region using full-disk H α images obtained from Big Bear Solar Observatory. We have measured the rate of helicity injection during the formation of the filament using full-disk 96 minute-cadence magnetograms taken by SOHO MDI. As a result we found that 1) no significant helicity was injected around the region (polarity inversion line; PIL) of filament formation and 2) negative helicity was injected in the decaying active region. The negative sign of the injected helicity was opposite to that of the filament helicity. On the other hand, at earlier times when the associated active region emerged and grew, positive helicity was intensively injected. Our results suggest that the magnetic helicity of the intermediate filament may have originated from the helicity accumulated during the period of the growth of its associated active region.

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“…One classification scheme (Engvold , 1998) provides a useful distinction between filaments forming inside and outside active regions. However, to understand the role that magnetic fields Fig.…”

Section: Global Formation Locationsmentioning

confidence: 99%

“…Based upon the magnetic environment in which they form, filaments may be split into three broad categories (Engvold (1998), see also Chapter 2):…”

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confidence: 99%

Formation and Large-Scale Patterns of Filament Channels and Filaments

Mackay

2014

Solar Prominences

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The properties and large-scale patterns of filament channels and filaments are considered. Initially, the global formation locations of filament channels and filaments are discussed, along with their hemispheric pattern. Next, observations of the formation of filament channels and filaments are described where two opposing views are considered. Finally, the wide range of models that have been constructed to consider the formation of filament channels and filaments over long time-scales are described, along with the origin of the hemispheric pattern of filaments.

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Observations of Filament Structure and Dynamics

Cited by 6 publications

References 29 publications

Prominence oscillations

Prominence oscillations

Magnetic Helicity Injection During the Formation of an Intermediate Filament

Formation and Large-Scale Patterns of Filament Channels and Filaments

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