Total Solar Eclipse Observations of Hot Prominence Shrouds

Habbal, Shadia Rifai; Druckmüller, Miloslav; Morgan, Huw; Scholl, Isabelle; Rusin, V.; Daw, A. N.; Johnson, J.; Arndt, M. B.

doi:10.1088/0004-637x/719/2/1362

Cited by 90 publications

(79 citation statements)

References 21 publications

(27 reference statements)

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“…Harvey (2001) reported that cavities are hot plasma inside the filament channels. An extensive discussion of the temperature effects in cavity regions was recently published by Habbal et al (2010Habbal et al ( , 2011; our results tend to confirm their conclusions. In principle, the extension of the cavity channel region can be evaluated, assuming no temporal change, thanks to rotation effects, see figure 13.…”

Section: Iv) Discussion and Conclusionsupporting

confidence: 88%

“…The deficiency values at 195A are surprisingly found to be only about 6.6 %, without taking into account the effect of the spurious scattered light (stray light effect). In this "hotter" emission line of about 1.5 MK the cavity contrast seems reduced, a result similar to the one recently described by Habbal et al (2010 and2011) and by Pasachoff et al (2011) for eclipse cavities. Moreover in Fig.…”

Section: ) Photometric Analysis Of the Cavity Regions In W-l With Ssupporting

confidence: 88%

“…The total eclipse of 11 th July 2010 (Pasachoff et al 2011and Habbal et al 2010-2011 for a description of the corona at this eclipse), allowed us to observe the true continuum between helium prominence lines (He I 4713A and Pα He II 4686A), taking into account faint low excitation emission lines using fast slitless spectra taken at the contacts, before and after the totality. These observations also yield relatively new results on the determination of the electron densities inside prominences when compared to previous photographic ground-based coronagraphic filtergram observations in the D3 line, where the continuum, at the location of the prominences, was not precisely measured (see Kubota and Leroy, 1970 for Lyotcoronagraph observations and Koutchmy, Lebecq and Stellmacher 1983 for eclipse broadband observations).…”

Section: I) Introductionmentioning

confidence: 99%

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Prominence Cavity Regions Observed Using SWAP 174 Å Filtergrams and Simultaneous Eclipse Flash Spectra

2012

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Abstract:Images from the SWAP (Proba 2 mission) taken at 174A in the Fe IX/X lines are compared to simultaneous slitless flash spectra taken during the last solar total eclipse of July, 11 th 2010. Many faint low excitation emission lines together with the HeI and HeII Paschen Alpha chromospheric lines are recorded on eclipse spectra where regions of limb prominences are obtained with space-borne imagers. We consider a deep flash spectrum obtained by summing 80 individual spectra to show the intensity modulations of the continuum. Intensity depressions are observed around the prominences in both eclipse and SWAP images. The prominence cavities are interpreted as a relative depression of plasma density, produced inside the corona surrounding the prominences. Photometric measurements are shown at different scales and different, spectrally narrow, intervals for both the prominences and the coronal background.

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Section: Iv) Discussion and Conclusionsupporting

confidence: 88%

Section: ) Photometric Analysis Of the Cavity Regions In W-l With Ssupporting

confidence: 88%

Section: I) Introductionmentioning

confidence: 99%

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Prominence Cavity Regions Observed Using SWAP 174 Å Filtergrams and Simultaneous Eclipse Flash Spectra

2012

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“…Coronal cavities are often observed to have cooler prominence plasma at their bases (Hudson et al 1999;Gibson et al 2006;Régnier et al 2011). The cavity is a region of relatively low-density high-temperature plasma (Gibson et al 2010;Habbal et al 2010). Berger et al (2011) have proposed that the prominence and its cavity are a form of magneto-thermal convective structure, macroscopically stable, but internally in a constant state of ubiquitous motions (Low et al 2012a,b).…”

Section: Introductionmentioning

confidence: 99%

A solar tornado triggered by flares?

Panesar

Innes

Tiwari

et al. 2013

A&A

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Context. Solar tornados are dynamical, conspicuously helical magnetic structures that are mainly observed as a prominence activity. Aims. We investigate and propose a triggering mechanism for the solar tornado observed in a prominence cavity by SDO/AIA on September 25, 2011. Methods. High-cadence EUV images from the SDO/AIA and the Ahead spacecraft of STEREO/EUVI are used to correlate three flares in the neighbouring active-region (NOAA 11303) and their EUV waves with the dynamical developments of the tornado. The timings of the flares and EUV waves observed on-disk in 195 Å are analysed in relation to the tornado activities observed at the limb in 171 Å. Results. Each of the three flares and its related EUV wave occurred within ten hours of the onset of the tornado. They have an observed causal relationship with the commencement of activity in the prominence where the tornado develops. Tornado-like rotations along the side of the prominence start after the second flare. The prominence cavity expands with the accelerating tornado motion after the third flare. Conclusions. Flares in the neighbouring active region may have affected the cavity prominence system and triggered the solar tornado. A plausible mechanism is that the active-region coronal field contracted by the "Hudson effect" through the loss of magnetic energy as flares. Subsequently, the cavity expanded by its magnetic pressure to fill the surrounding low corona. We suggest that the tornado is the dynamical response of the helical prominence field to the cavity expansion.

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“…The structure often contains a twisted flux tube able to accumulate magnetic energy and mass within it, which thus can be destabilised by catastrophic mechanisms and/or external triggers. Despite several studies of the thermal structures of cavities especially from white-light coronographs, eclipse observations, EUV, and soft X-ray imaging (e.g., Hudson et al 1999;Hudson & Schwenn 2000;Gibson et al 2006;Habbal et al 2010), there is to our knowledge no observational evidence of a long time series and of high-cadence obsevations of cavity at different temperatures as provided by SDO/AIA data able to (i) clearly demonstrate the thermal structure of both the prominence and cavity material, and (ii) describe how the plasma of a polar-crown filament evolves before and during the eruption. Thus, the observations described here focus for the first time on the dynamics of the inner part of the cavity above the polar crown filament/prominence material and its evolution during the eruptive phase.…”

Section: Introductionmentioning

confidence: 99%

A new look at a polar crown cavity as observed by SDO/AIA

Régnier

Walsh²,

Alexander³

2011

A&A

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Context. The Solar Dynamics Observatory (SDO) was launched in February 2010 and is now providing an unprecedented view of the solar activity at high spatial resolution and high cadence covering a broad range of temperature layers of the atmosphere. Aims. We aim at defining the structure of a polar crown cavity and describing its evolution during the erupting process. Methods. We use the high-cadence time series of SDO/AIA observations at 304 Å (50 000 K) and 171 Å (0.6 MK) to determine the structure of the polar crown cavity and its associated plasma, as well as the evolution of the cavity during the different phases of the eruption. We report on the observations recorded on 13 June 2010 located on the north-west limb. Results. We observe coronal plasma shaped by magnetic field lines with a negative curvature (U-shape) sitting at the bottom of a cavity. The cavity is located just above the polar crown filament material. We thus observe the inner part of the cavity above the filament as depicted in the classical three part coronal mass ejection (CME) model composed of a filament, a cavity, and a CME front. The filament (in this case a polar crown filament) is part of the cavity, and it makes a continuous structuring from the filament to the CME front depicted by concentric ellipses (in a 2D cartoon). Conclusions. We propose to define a polar crown cavity as a density depletion sitting above denser polar crown filament plasma drained down the cavity by gravity. As part of the polar crown filament, plasma at different temperatures (ranging from 50 000 K to 0.6 MK) is observed at the same location on the cavity dips and sustained by a competition between the gravity and the curvature of magnetic field lines. The eruption of the polar crown cavity as a solid body can be decomposed into two phases: a slow rise at a speed of 0.6 km s −1 and an acceleration phase at a mean speed of 25 km s −1 .

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Total Solar Eclipse Observations of Hot Prominence Shrouds

Cited by 90 publications

References 21 publications

Prominence Cavity Regions Observed Using SWAP 174 Å Filtergrams and Simultaneous Eclipse Flash Spectra

Prominence Cavity Regions Observed Using SWAP 174 Å Filtergrams and Simultaneous Eclipse Flash Spectra

A solar tornado triggered by flares?

A new look at a polar crown cavity as observed by SDO/AIA

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