Persistent Horizontal Flows and Magnetic Support of Vertical Threads in a Quiescent Prominence

Chae, Jongchul; Ahn, Kwangsoo; Lim, Eun-Kyung; Choe, G. S.; Sakurai, Takashi

doi:10.1086/595785

Cited by 71 publications

(73 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, we do see signatures of strands in the AIA 211Å and particularly in the 304Å images. The bottom panels of the movie display plasma flows along the arcades, stretching to the right, that are generally parallel to the solar limb, similar to those described in Chae et al (2008) and Orozco Suárez, Asensio Ramos, and Trujillo Bueno (2014). On the other side of the prominence body, one can see clumps of plasma flowing mostly toward the limb only in the AIA 304Å passband.…”

Section: Morphology Dynamics and Evolution Of The Target Prominencesupporting

confidence: 56%

Spectral Characteristics of the He i D3 Line in a Quiescent Prominence Observed by THEMIS

et al. 2017

View full text Add to dashboard Cite

We analyze the observations of a quiescent prominence acquired by the Téléscope Heliographique pour l'Étude du Magnetisme et des Instabilités Solaires (THEMIS) in the He i 5876Å (He i D3) multiplet aiming to measure the spectral characteristics of the He i D3 profiles and to find for them an adequate fitting model. The component characteristics of the He i D3 Stokes I profiles are measured by the fitting system approximating them with a double Gaussian. This model yields an He i D3 component peak intensity ratio of 5.5 ± 0.4, which differs from the value of 8 expected in the optically thin limit. Most of the measured Doppler velocities lie in the interval ±5 km s −1 , with a standard deviation of ±1.7 km s −1 around the peak value of 0.4 km s −1 . The wide distribution of the full-width at half maximum has two maxima at 0.25Å and 0.30Å for the He i D3 blue component and two maxima at 0.22Å and 0.31Å for the red component. The width ratio of the components is 1.04 ± 0.18. We show that the double-Gaussian model systematically underestimates the blue wing intensities. To solve this problem, we invoke a two-temperature multiGaussian model, consisting of two double-Gaussians, which provides a better representation of He i D3 that is free of the wing intensity deficit. This model suggests temperatures of 11.5 kK and 91 kK, respectively, for the cool and the hot component of the target prominence. The cool and hot components of a typical He i D3 profile have component peak intensity ratios of 6.6 and 8, implying a prominence geometrical width of 17 Mm and an optical thickness of 0.3 for the cool component, while the optical thickness of the hot component is negligible. These prominence parameters seem to be realistic, suggesting the physical adequacy of the multi-Gaussian model with important implications for interpreting He i D3 spectropolarimetry by current inversion codes.

show abstract

Section: Morphology Dynamics and Evolution Of The Target Prominencesupporting

confidence: 56%

Spectral Characteristics of the He i D3 Line in a Quiescent Prominence Observed by THEMIS

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Structures with simi- lar features are being reported in prominences, as matter detaching from the main structure. Such observations take place mostly for quiescent rather than active prominences (or filaments), with high resolution instruments such as SST/CRISP, Hinode/SOT and SDO/AIA (Chae et al 2008;Lin 2010;Zapiór and Rudawy 2010;Berger et al 2010;Hillier, Isobe, and Watanabe 2011;Liu, Berger, and Low 2012). Apart from eruptive prominences or cases of ejected blobs (where velocities are usually high), the reported velocities for these prominence blobs are often on the order of 30 km s −1 , values that are usually much lower than the average values for coronal rain blobs (in average 60-70 km s −1 ).…”

Section: Discussionmentioning

confidence: 99%

On-Disk Coronal Rain

2012

View full text Add to dashboard Cite

Small and elongated, cool and dense blob-like structures are being reported with high resolution telescopes in physically different regions throughout the solar atmosphere. Their detection and the understanding of their formation, morphology and thermodynamical characteristics can provide important information on their hosting environment, especially concerning the magnetic field, whose understanding constitutes a major problem in solar physics. An example of such blobs is coronal rain, a phenomenon of thermal nonequilibrium observed in active region loops, which consists of cool and dense chromospheric blobs falling along loop-like paths from coronal heights. So far, only off-limb coronal rain has been observed and few reports on the phenomenon exist. In the present work, several datasets of on-disk Hα observations with the CRisp Imaging SpectroPolarimeter (CRISP) at the Swedish 1-m Solar Telescope (SST) are analyzed. A special family of on-disk blobs is selected for each dataset and a statistical analysis is carried out on their dynamics, morphology and temperatures. All characteristics present distributions which are very similar to reported coronal rain statistics. We discuss possible interpretations considering other similar blob-like structures reported so far and show that a coronal rain interpretation is the most likely one. Their chromospheric nature and the projection effects (which eliminate all direct possibility of height estimation) on one side, and their small sizes, fast dynamics, and especially, their faint character (offering low contrast with the background intensity) on the other side, are found as the main causes for the absence until now of the detection of this on-disk coronal rain counterpart.

show abstract

“…Observations by the Solar and Heliospheric Observatory (SoHO; Brekke et al 1997;Winebarger et al 2002), TRACE (Winebarger et al 2001) and Hinode (Chae et al 2008;Ofman & Wang 2008;Terradas et al 2008) showed that flows are ubiquitously present in active region loops. Hence, it is important to study how flows in coronal loops modify the properties of kink oscillations.…”

Section: Introductionmentioning

confidence: 99%

Kink oscillations of cooling coronal loops with variable cross-section

Shukhobodskiy

Erdélyi

2017

A&A

View full text Add to dashboard Cite

We study kink waves and oscillations in a thin expanding magnetic tube in the presence of flow. The tube consists of a core region and a thin transitional region at the tube boundary. In this region the plasma density monotonically decreases from its value in the core region to the value outside the tube. Both the plasma density and velocity of background flow vary along the tube and in time. Using the multiscale expansions we derive the system of two equations describing the kink oscillations. When there is no transitional layer the oscillations are described by the first of these two equations. We use this equation to study the effect of plasma density variation with time on kink oscillations of an expanding tube with a sharp boundary. We assume that the characteristic time of the density variation is much greater than the characteristic time of kink oscillations. Then we use the Wentzel-Kramer-Brillouin (WKB) method to derive the expression for the adiabatic invariant, which is the quantity that is conserved when the plasma density varies. The general theoretical results are applied to the kink oscillations of coronal magnetic loops. We consider an expanding loop with the half-circle shape and assume that the plasma temperature inside a loop decays exponentially with time. We numerically calculated the dependences of the fundamental mode frequency, the ratio of frequencies of the first overtone and fundamental mode, and the oscillation amplitude on time. We obtained that the oscillation frequency and amplitude increase and the frequency ratio decreases due to cooling. The amplitude increase is stronger for loops with a greater expansion factor. This effect is also more pronounced for higher loops. However, it is fairly moderate even for loops that are quite high.

show abstract

Persistent Horizontal Flows and Magnetic Support of Vertical Threads in a Quiescent Prominence

Cited by 71 publications

References 21 publications

Spectral Characteristics of the He i D3 Line in a Quiescent Prominence Observed by THEMIS

Spectral Characteristics of the He i D3 Line in a Quiescent Prominence Observed by THEMIS

On-Disk Coronal Rain

Kink oscillations of cooling coronal loops with variable cross-section

Contact Info

Product

Resources

About