Prominence fine structures in a magnetic equilibrium: 
Two-dimensional models with multilevel radiative transfer

Heinzel, P.; Anzer, U.

doi:10.1051/0004-6361:20010926

Cited by 96 publications

(126 citation statements)

References 8 publications

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“…These 2D models were developed by Heinzel & Anzer (2001). These threads are uniform in the vertical direction and the variation in all quantities takes place only in the horizontal plane parallel to the solar surface.…”

Section: Prominence Fine-structure Modelsmentioning

confidence: 99%

“…These threads are uniform in the vertical direction and the variation in all quantities takes place only in the horizontal plane parallel to the solar surface. The 2D threads are in the MHS equilibrium of Kippenhahn-Schlüter type (Kippenhahn & Schlüter 1957) that was generalized to 2D by Heinzel & Anzer (2001) and their temperature structure is specified empirically to encompass both the central cool part and also the prominence-to-corona transition region (PCTR, see Anzer & Heinzel 1999). The PCTR exhibits two distinct forms.…”

Section: Prominence Fine-structure Modelsmentioning

confidence: 99%

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Dynamics of quiescent prominence fine structures analyzed by 2D non-LTE modelling of the Hα line

Gunár

Mein

Schmieder

et al. 2012

A&A

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Aims. We analyze the dynamics of the prominence fine structures of a quiescent prominence observed on April 26, 2007 during a coordinated campaign of several spaceborne and ground-based instruments. We use Lyman spectra observed by SOHO/SUMER and the Hα line spectra obtained by MSDP spectrograph working at the Meudon Solar Tower. Methods. We employ the 2D multi-thread prominence fine-structure modelling that includes randomly distributed line-of-sight (LOS) velocities of individual threads to derive models producing synthetic Lyman lines in good agreement with the SOHO/SUMER observations. We then use these models to produce synthetic Hα line spectra that we compare with the observed spectra using three statistical parameters: the line integrated intensity, the line full-width at half-maximum (FWHM), and the Doppler velocity derived from shifts of the line profiles. Results. We demonstrate that the 2D multi-thread models that produce synthetic Lyman spectra in agreement with observations also generate synthetic Hα spectra in good agreement with the observed ones. The statistical analysis of the FWHM and Doppler velocities of the synthetic Hα line profiles show that the overall LOS velocities in the April 26, 2007 prominence at the time of the observations were below 15 km s −1 and in the prominence core were close to 10 km s −1 . In combination with the analysis of the Lyman spectra, we determine several physical parameters of the observed prominence fine-structures that show that the April 26, 2007 prominence had a relatively low-mass weakly magnetized structure. We are also able to impose some constraints on the prominence core temperature, which may be relatively low, with values below 6000 K. Conclusions. The combination of 2D non-LTE prominence fine-structure modelling with the statistical analysis of the observed and synthetic Lyman and Hα spectra allows us to analyze the influence of the model input parameters and the velocity fields on the synthetic Hα line profiles, thus determine the overall dynamics of the observed prominence as well as the physical parameters of its plasma.

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Section: Prominence Fine-structure Modelsmentioning

confidence: 99%

Section: Prominence Fine-structure Modelsmentioning

confidence: 99%

Dynamics of quiescent prominence fine structures analyzed by 2D non-LTE modelling of the Hα line

Gunár

Mein

Schmieder

et al. 2012

A&A

Self Cite

View full text Add to dashboard Cite

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“…This was followed by Anzer & Heinzel (1998, 1999, who developed 1D magnetohydrostatic equilibrium models of the Kippenhahn-Schlüter (K-S) type. These were generalized into 2D by Heinzel & Anzer (2001), whose prominence fine-structure models take the form of 2D vertically infinite plasma threads in magnetohydrostatic equilibrium, suspended in magnetic dips. The temperature structure of these prominence fine-structure threads is described semi-empirically and includes the prominence-corona transition region (PCTR).…”

Section: Introductionmentioning

confidence: 99%

Non-LTE modelling of prominence fine structures using hydrogen Lyman-line profiles

Schwartz

Gunár

Curdt

2015

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Aims. We perform a detailed statistical analysis of the spectral Lyman-line observations of the quiescent prominence observed on May 18, 2005. Methods. We used a profile-to-profile comparison of the synthetic Lyman spectra obtained by 2D single-thread prominence finestructure model as a starting point for a full statistical analysis of the observed Lyman spectra. We employed 2D multi-thread finestructure models with random positions and line-of-sight velocities of each thread to obtain a statistically significant set of synthetic Lyman-line profiles. We used for the first time multi-thread models composed of non-identical threads and viewed at line-of-sight angles different from perpendicular to the magnetic field. Results. We investigated the plasma properties of the prominence observed with the SoHO/SUMER spectrograph on May 18, 2005 by comparing the histograms of three statistical parameters characterizing the properties of the synthetic and observed line profiles. In this way, the integrated intensity, Lyman decrement ratio, and the ratio of intensity at the central reversal to the average intensity of peaks provided insight into the column mass and the central temperature of the prominence fine structures.

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“…For intermediate filaments, recent extrapolation models (Aulanier & Démoulin 1998;Mackay & van Ballegooijen 2009;Dudík et al 2008Dudík et al , 2012 have clearly shown that the feet of filaments consist of small threads that are part of long magnetic field lines. These threads are formed by accumulating plasma in dips of the field lines (Heinzel & Anzer 2001;Hillier & van Ballegooijen 2013). In this type of filament, feet are related to parasitic polarities, however they are not rooted in them.…”

Section: Introductionmentioning

confidence: 99%

Proper horizontal photospheric flows in a filament channel

Schmieder

Roudier

Mein

et al. 2014

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Context. An extended filament in the central part of the active region NOAA 11106 crossed the central meridian on Sept. 17, 2010 in the southern hemisphere. It has been observed in Hα with the THEMIS telescope in the Canary Islands and in 304 Å with the EUV imager (AIA) onboard the Solar Dynamic Observatory (SDO). Counterstreaming along the Hα threads and bright moving blobs (jets) along the 304 Å filament channel were observed during 10 h before the filament erupted at 17:03 UT. Aims. The aim of the paper is to understand the coupling between magnetic field and convection in filament channels and relate the horizontal photospheric motions to the activity of the filament.Methods. An analysis of the proper photospheric motions using SDO/HMI continuum images with the new version of the coherent structure tracking (CST) algorithm developed to track granules, as well as the large scale photospheric flows, was performed for three hours. Using corks, we derived the passive scalar points and produced a map of the cork distribution in the filament channel. Averaging the velocity vectors in the southern hemisphere in each latitude in steps of 3.5 arcsec, we defined a profile of the differential rotation. Results. Supergranules are clearly identified in the filament channel. Diverging flows inside the supergranules are similar in and out of the filament channel. Converging flows corresponding to the accumulation of corks are identified well around the Hα filament feet and at the edges of the EUV filament channel. At these convergence points, the horizontal photospheric velocity may reach 1 km s −1 , but with a mean velocity of 0.35 km s −1 . In some locations, horizontal flows crossing the channel are detected, indicating eventually large scale vorticity. Conclusions. The coupling between convection and magnetic field in the photosphere is relatively strong. The filament experienced the convection motions through its anchorage points with the photosphere, which are magnetized areas (ends, feet, lateral extensions of the EUV filament channel). From a large scale point-of-view, the differential rotation induced a shear of 0.1 km s −1 in the filament. From a small scale point-of-view, any convective motions favored the interaction of the parasitic polarities responsible for the anchorages of the filament to the photosphere with the surrounding network and may explain the activity of the filament.

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Prominence fine structures in a magnetic equilibrium: Two-dimensional models with multilevel radiative transfer

Cited by 96 publications

References 8 publications

Dynamics of quiescent prominence fine structures analyzed by 2D non-LTE modelling of the Hα line

Dynamics of quiescent prominence fine structures analyzed by 2D non-LTE modelling of the Hα line

Non-LTE modelling of prominence fine structures using hydrogen Lyman-line profiles

Proper horizontal photospheric flows in a filament channel

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