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Engvold, O.; Jakobsson, Hans; Tandberg-Hanssen, E.; Gurman, J. B.; Moses, D.

doi:10.1023/a:1012285218862

Cited by 32 publications

(19 citation statements)

References 6 publications

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“…Recent studies of flux emergence during the slow rise phase (Feynman & Ruzmaikin 2004;Sterling et al 2007), its relation to CME initiation (Zhang et al 2008), observations of heating both before (e.g., Cirigliano et al 2004;Kucera & Landi 2006) and during eruptions (e.g., Engvold et al 2001;Kucera & Landi 2008), and increases in the size of the cavity (Gibson et al 2006) contribute pieces to the puzzle of determining the mechanism driving filament eruptions, and they help to place the results of this study into context.…”

Section: Introductionmentioning

confidence: 81%

Mass Composition in Pre-Eruption Quiet Sun Filaments

Kilper¹,

Gilbert²,

Alexander³

2009

ApJ

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Filament eruptions are extremely important phenomena due to their association with coronal mass ejections and their effects on space weather. Little is known about the filament mass and composition in the eruption process, since most of the related research has concentrated on the evolution and disruption of the magnetic field. Following up on our previous work, we present here an analysis of nineteen quiet Sun filament eruptions observed by Mauna Loa Solar Observatory in Hα and He i 10830 Å that has identified a compositional precursor common to all of these eruptions. There is a combined trend of an apparent increase in the homogenization of the filament mass composition, with concurrent increases in absorption in Hα and He i and in the level of activity, all starting at least one day prior to eruption. This finding suggests that a prolonged period of mass motions, compositional mixing, and possibly even extensive mass loading is occurring during the build up of these eruptions.

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Section: Introductionmentioning

confidence: 81%

Mass Composition in Pre-Eruption Quiet Sun Filaments

Kilper¹,

Gilbert²,

Alexander³

2009

ApJ

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“…Is the cool material heated, making a halo around the prominence as suggested by Engvold et al (2001), or is this halo just due to diffuse emission )? -Is the assumption of the non-existence of a void completly justified?…”

Section: Discussionmentioning

confidence: 99%

Spectroscopic diagnostics of an Hα and EUV filament observed with THEMIS and SOHO

Schmieder

Tziotziou²,

Heinzel³

2003

A&A

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Abstract.A long filament has been observed with THEMIS/MSDP and SOHO/CDS -SUMER, during a coordinated campaign (JOPs 131/95) on May 5, 2000. The data were (a) 2-D Hα spectra, observed using THEMIS, (b) Lyman series spectra and Lyman continuum, observed using SOHO/SUMER, and (c) EUV spectra (in O  629 Å, Mg  624 Å, Si  520 Å, Ca  557 Å and He  584 Å) observed using SOHO/CDS. A large depression of the line emissions in CDS images represents the EUV filament. A computed model shows that the EUV filament consists of an extended in height cloud of low gas pressure at an altitude lower than the top of the Hα filament, volume-blocking and absorbing coronal emission and absorbing transition region line emission. The optical thickness of the Lyman continuum is estimated by using the ratio of O  intensity inside and outside the EUV filament, while the optical thickness of Hα is computed from the Hα line profile by using an inversion technique. Using simultaneous Hα, Lyman lines and Lyman continuum spectroscopic data, we performed detailed, non-LTE radiative transfer diagnostics of the filament plasma conditions. The optical thickness of the Lyman continuum is larger than that of the Hα line by one to two orders of magnitude. This could be of a great importance for filament formation modeling, if we consider that more cool material exists in filament channels but is optically too thin to be visible in Hα images.

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“…This shows up as an increase of mass or turbulent motion inside and at the structure footpoints (for example, as shown in Figure 27), fragmentary brightening and fading due to sporadic heating events (e.g., Ofman et al, 1998;Schmieder et al, 2000;Kucera and Landi, 2008), EUV brightenings due to reconnections, deformation and helical rotation of the filament (Sterling et al, 2011), and the start of lifting off (e.g., Gilbert et al, 2000;Engvold et al, 2001;Sterling and Moore, 2004;Bemporad, 2009;Liewer et al, 2009). Figure 28 shows a further example of these pre-erupting signatures: the Hα intensity variation in a segment of a filament, which will start disappearing at around 12:30 UT.…”

Section: Observed Precursors Of Eruptionsmentioning

confidence: 99%

Solar Prominences: Observations

Parenti

2014

Living Rev. Solar Phys.

284

234

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Solar prominences are one of the most common features of the solar atmosphere. They are found in the corona but they are one hundred times cooler and denser than the coronal material, indicating that they are thermally and pressure isolated from the surrounding environment. Because of these properties they appear at the limb as bright features when observed in the optical or the EUV cool lines. On the disk they appear darker than their background, indicating the presence of a plasma absorption process (in this case they are called filaments). Prominence plasma is embedded in a magnetic environment that lies above magnetic inversion lines, denoted a filament channel.This paper aims at providing the reader with the main elements that characterize these peculiar structures, the prominences and their environment, as deduced from observations. The aim is also to point out and discuss open questions on prominence existence, stability and disappearance.The review starts with a general introduction of these features and the instruments used for their observation. Section 2 presents the large scale properties, including filament morphology, thermodynamical parameters, magnetic fields, and the properties of the surrounding coronal cavity, all in stable conditions. Section 3 is dedicated to small-scale observational properties, from both the morphological and dynamical points of view. Section 4 introduces observational aspects during prominence formation, while Section 5 reviews the sources of instability leading to prominence disappearance or eruption. Conclusions and perspectives are given in Section 6.

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Cited by 32 publications

References 6 publications

Mass Composition in Pre-Eruption Quiet Sun Filaments

Mass Composition in Pre-Eruption Quiet Sun Filaments

Spectroscopic diagnostics of an Hα and EUV filament observed with THEMIS and SOHO

Solar Prominences: Observations

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