Structure and evolution of velocities in quiescent filaments

Martres, M. J.; Mein, P.; Schmieder, B.; Soru-Escaut, I.

doi:10.1007/bf00149996

Cited by 33 publications

(13 citation statements)

References 8 publications

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“…These flows have not, to the best of our knowledge, been previously described in over a century of ground-based observations. They are much higher velocity than the upflows measured in filament Ha Doppler observations (e.g., 3 km s ; Martres et al 1981) Ϫ1 but are perhaps consistent with later higher resolution observations (e.g., 5-20 km s ; Zirker et al 1998). It is unclear…”

Section: Discussionsupporting

confidence: 55%

“…Observations of filaments on the disk show that they are indeed resolvable into thin horizontal threads, often with measurable motions along the threads and up-or downflows in the footpoint regions (Kubota & Uesegi 1986;Zirker et al 1998;Lin et al 2005). However, observations of vertically striated or "hedgerow" prom- inences often show vertical filamentary downflows (Engvold 1981;Martres et al 1981) and vortices (Liggett & Zirin 1984). Reconciliation of the models with these observations of vertical and rotational flows remains a major goal of prominence physics.…”

Section: Introductionmentioning

confidence: 99%

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Hinode SOT Observations of Solar Quiescent Prominence Dynamics

Berger

Shine

Slater

et al. 2008

ApJ

247

243

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We report findings from multihour 0.2Љ resolution movies of solar quiescent prominences (QPs) observed with the Solar Optical Telescope (SOT) on the Hinode satellite. The observations verify previous findings of filamentary downflows and vortices in QPs. SOT observations also verify large-scale transverse oscillations in QPs, with periods of 20-40 minutes and amplitudes of 2-5 Mm. The upward propagation speed of several waves is found to be ∼10 km s , comparable to the sound speed of a 10,000 K plasma, implying that the waves are magnetoacoustic in and Ha bandpasses of SOT. The new flows are seen in about half of the QPs observed by SOT to date. The dark upflows resemble buoyant starting plumes in both their velocity profile and flow structure. We discuss thermal and magnetic mechanisms as possible causes of the plumes.

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Section: Discussionsupporting

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Hinode SOT Observations of Solar Quiescent Prominence Dynamics

Berger

Shine

Slater

et al. 2008

ApJ

247

243

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“…Doppler measurements in these quiescent filaments A&A 542, A112 (2012) (e.g., Martres et al 1981;Schmieder et al 2010) have revealed that a wide range of velocities coexist in the same structure. For example, the recent study by Chae et al (2007) reported lineof-sight (LOS) velocities between ±5 km s −1 and ±15 km s −1…”

Section: Introductionmentioning

confidence: 98%

An active region filament studied simultaneously in the chromosphere and photosphere

Kuckein

Pillet

Centeno

2012

A&A

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Context. Paper I presents the magnetic structure, inferred for the photosphere and the chromosphere, of a filament that developed in active region (AR) NOAA 10781, observed on 2005 July 3 and July 5. Aims. In this paper we complement those results with the velocities retrieved from Doppler shifts measured at the chromosphere and the photosphere in the AR filament area.Methods. The velocities and magnetic field parameters were inferred from full Stokes inversions of the photospheric Si i 10 827 Å line and the chromospheric He i 10 830 Å triplet. Various inversion methods with different numbers of atmospheric components and different weighting schemes of the Stokes profiles were used. The velocities were calibrated on an absolute scale. Results. A ubiquitous chromospheric downflow is found in the faculae surrounding the filament, with an average velocity of 1.6 km s −1 . The filament region, however, displays upflows in the photosphere on both days, when the linear polarization (which samples the transverse component of the fields) is given more weight in the inversions. The upflow speeds of the transverse fields in the filament region average −0.15 km s −1 . In the chromosphere, the situation is different for the two days of observation. On July 3, the chromospheric portion of the filament is moving upward as a whole with a mean speed of −0.24 km s −1 . However, on July 5 only the section above an orphan penumbra shows localized upflow patches, while the rest of the filament is dominated by the same downflows observed elsewhere in the facular region. Photospheric supersonic downflows that last for tens of minutes are detected below the filament, close to the PIL. Conclusions. The observed velocity pattern in this AR filament strongly suggests a scenario where the transverse fields are mostly dominated by upflows. The filament flux rope is seen to be emerging at all places and both heights, with a few exceptions in the chromosphere. This happens within a surrounding facular region that displays a generalized downflow in the chromosphere and localized downflows of supersonic character at the photosphere. No large scale downflow of transverse field lines is observed at the photosphere.

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“…The mechanism generating such magnetic configurations must take into account photospheric motions. Martres et al (1981) found a photospheric velocity field beneath a filament in which lines of zero radial velocity were roughly perpendicular to the direction of the filament. Martin et al (1985) observed that the formation and evolution of filaments is linked to converging photospheric motions perpendicular to the polarity inversion line (PIL).…”

Section: Introductionmentioning

confidence: 99%

Photospheric flows around a quiescent filament

Rondi¹,

Roudier²,

Molodij

et al. 2007

A&A

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Context. The horizontal photospheric flows below and around a filament are one of the components in the formation and evolution of filaments. Few studies exist because they require multiwalength time sequences at high spatial resolution. Aims. Our objective is to measure the horizontal photospheric flows associated with the evolution and eruption of a filament. Methods. We present observations obtained in 2004 during the international JOP 178 campaign which involved eleven instruments both in space and at ground based observatories. We use TRACE WL, DOT and DST observation to derive flow maps which are then coaligned with intensity images and with the vector magnetic field map obtained with THEMIS/MTR. Results. Several supergranulation cells cross the Polarity Inversion Line (PIL) and can transport magnetic flux through the PIL, in particular parasitic polarities. We present a detailed example of the formation of a secondary magnetic dip at the location of a filament footpoint. Large-scale converging flows, which could exist along the filament channel and contribute to its formation, are not observed. Before the filament's eruptive phase, we observe both parasitic and normal polarities being swept by a continuously diverging horizontal flow located in the filament gap. The disappearance of the filament initiates in this gap. Such purely horizontal motions could lead to destabilization of the filament and could trigger the sudden filament disappearance.

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Structure and evolution of velocities in quiescent filaments

Cited by 33 publications

References 8 publications

Hinode SOT Observations of Solar Quiescent Prominence Dynamics

Hinode SOT Observations of Solar Quiescent Prominence Dynamics

An active region filament studied simultaneously in the chromosphere and photosphere

Photospheric flows around a quiescent filament

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