Stereoscopic Analysis of the 19 May 2007 Erupting Filament

Liewer, P. C.; Jong, E. M. De; Hall, J. R.; Howard, R. A.; Thompson, W. T.; Culhane, J. L.; Bone, L.; Driel-Gesztelyi, L. van

doi:10.1007/s11207-009-9363-4

Cited by 96 publications

(110 citation statements)

References 23 publications

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“…The stereoscopic reconstructions using SECCHI/EUVI observations of 19 May 2007 filament eruption event were reported recently by (Liewer et al, 2009) and (Gissot et al, 2008). While Liewer et al, (2009) used scc measure for reconstruction, Gissot et al, (2008) used optical flow method to find displacements between features in stereoscopic pairs of SECCHI/EUVI 304Å images.…”

Section: Discussionmentioning

confidence: 97%

“…However, the main source of error that remains is the error in identification of the filament spine in STEREO-B, as it appears quite differently in both images. An estimate of error in determination of height using this technique was given by Liewer et al, (2009). They relate the error in locating the common feature in the image to an error in height by the relation ∆h ≈ ∆x/sinφ, where ∆x is the error in locating common feature in pixels and φ is the separation angle of the two spacecraft.…”

Section: Height Measurement Using Scc Measurementioning

confidence: 99%

“…The disadvantage of this method being: (i) it measures only the projected height, (ii) non-availability of magnetograms due to its location at the limb, (iii) can not be used to follow height evolution for several days and (iv) no continuity of multi-temperature observations. Only recently, with the advent of stereoscopic observations by the twin spacecraft of the Solar Terrestrial Relations Observatory (STEREO) mission called STEREO-A (Ahead) and STEREO-B (Behind), the true height of filament can be judged properly and the heating of the plasma can be tested (Kaiser et al, 2008); (Gissot et al, 2008); (Liewer et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

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3D Evolution of a Filament Disappearance Event Observed by STEREO

Gosain

Schmieder²,

Venkatakrishnan³

et al. 2009

Sol Phys

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A filament disappearance event was observed on 22 May 2008 during our recent campaign JOP 178. The filament, situated in the southern hemisphere, showed sinistral chirality consistent with the hemispheric rule. The event was well observed by several observatories in particular by THEMIS. One day before the disappearance, Hα observations showed up and down flows in adjacent locations along the filament, which suggest plasma motions along twisted flux rope. THEMIS and GONG observations show shearing photospheric motions leading to magnetic flux canceling around barbs. STEREO A, B spacecraft with separation angle 52.4 degrees, showed quite different views of this untwisting flux rope in He II 304Å images. Here, we reconstruct the 3D geometry of the filament during its eruption phase using STEREO EUV He II 304Å images and find that the filament was highly inclined to the solar normal. The He II 304Å movies show individual threads, which oscillate and rise to an altitude of about 120 Mm with apparent velocities of about 100 km s −1 , during the rapid evolution phase. Finally, as the flux rope expands into the corona, the filament disappears by becoming optically thin to undetectable levels. No CME was detected by STEREO, only a faint CME was recorded by LASCO at the beginning of the disappearance phase at 02:00 UT, which could be due to partial filament eruption. Further, STEREO Fe XII 195Å images showed bright loops beneath the filament prior to the disappearance phase, suggesting magnetic reconnection below the flux rope.

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Section: Discussionmentioning

confidence: 97%

Section: Height Measurement Using Scc Measurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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3D Evolution of a Filament Disappearance Event Observed by STEREO

Gosain

Schmieder²,

Venkatakrishnan³

et al. 2009

Sol Phys

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“…An obvious eruption to consider is one that occurred in the same active region, but on the previous day, on 2007 May 19 starting near 12:00 UT. That event was analyzed by Li et al (2008), Liewer et al (2009) and Bone et al (2009), while Veronig et al (2008) focused on a coronal wave generated from that eruption. Alas however, those workers show that the May 19 event mainly occurred on a different PIL from the May 20 event of this paper, with the primary filament of the May 19 event located in the PIL west of that of the May 20 event (see in particular Bone et al 2009).…”

Section: Discussionmentioning

confidence: 99%

Evidence for magnetic flux cancelation leading to an ejective solar eruption observed byHinode,TRACE,STEREO, andSoHO/MDI

Sterling¹,

Chifor²,

Mason³

et al. 2010

A&A

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Aims. We study the onset of a solar eruption involving a filament ejection on 2007 May 20. Methods. We observe the filament in Hα images from Hinode/SOT and in EUV with TRACE and STEREO/SECCHI/EUVI. Hinode/XRT images are used to study the eruption in soft X-rays. From spectroscopic data taken with Hinode/EIS we obtain bulkflow velocities, line profiles, and plasma densities in the onset region. The magnetic field evolution was observed in SoHO/MDI magnetograms. Results. We observed a converging motion between two opposite polarity sunspots that form the primary magnetic polarity inversion line (PIL), along which resides filament material before eruption. Positive-flux magnetic elements, perhaps moving magnetic features (MMFs) flowing from the spot region, appear north of the spots, and the eruption onset occurs where these features cancel repeatedly in a negative-polarity region north of the sunspots. An ejection of material observed in Hα and EUV marks the start of the filament eruption (its "fast-rise"). The start of the ejection is accompanied by a sudden brightening across the PIL at the jet's base, observed in both broad-band images and in EIS. Small-scale transient brightenings covering a wide temperature range (Log T e = 4.8−6.3) are also observed in the onset region prior to eruption. The preflare transient brightenings are characterized by sudden, localized density enhancements (to above Log n e [cm −3 ] = 9.75, in Fe xiii) that appear along the PIL during a time when pre-flare brightenings were occurring. The measured densities in the eruption onset region outside the times of those enhancements decrease with temperature.Persistent downflows (red-shifts) and line-broadening (Fe xii) are present along the PIL.Conclusions. The array of observations is consistent with the pre-eruption sheared-core magnetic field being gradually destabilized by evolutionary tether-cutting flux cancelation that was driven by converging photospheric flows, and the main filament ejection being triggered by flux cancelation between the positive flux elements and the surrounding negative field. A definitive statement however on the eruption's ultimate cause would require comparison with simulations, or additional detailed observations of other eruptions occurring in similar magnetic circumstances.

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“…The rather small scale of the twisted coronal structures does not allow us to see differences in SECCHI/EUVI images of STEREO-A and STEREO-B spacecrafts with separation of only near 10 • in June 2003 as it is able to do for more large scale erupting structures (Gissot et al, 2008;Liewer et al, 2009). Figure 5 shows enlarged images of the twisted structure obtained by both STEREO A and B spacecraft.…”

Section: Trace and Stereo/secchi/euvi Observationsmentioning

confidence: 95%

Multiwavelength Study of the M8.9/3B Solar Flare from AR NOAA 10960

et al. 2010

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We present a multiwavelength analysis of a long duration white-light solar flare (M8.9/3B) event that occurred on 04 June 2007 from AR NOAA 10960. The flare was observed by several spaceborne instruments, namely SOHO/MDI, HINODE/SOT, TRACE and STEREO/SECCHI. The flare was initiated near a small, positive-polarity, satellite sunspot at the centre of the active region, surrounded by opposite-polarity field regions. MDI images of the active region show considerable amount of changes in the small positive-polarity sunspot of δ configuration during the flare event. SOT/G-band (4305Å) images of the sunspot also suggest the rapid evolution of this positive-polarity sunspot with highly twisted penumbral filaments before the flare event, which were oriented in a counterclockwise direction. It shows the change in orientation, and also remarkable disapperance of twisted penumbral filaments (≈35 -40%) and enhancement in umbral area (≈45 -50 %) during the decay phase of the flare event. TRACE and SECCHI observations reveal the successive activation of two helical-twisted structures associated with this sunspot, and the corresponding brightening in the chromosphere as observed by the time-sequence images of SOT/Ca ii H line (3968Å). The secondary, helical-twisted structure is found to be associated with the M8.9 flare event. The brightening starts six-seven minutes prior to the flare maximum with the appearance of secondary, helical-twisted structure. The flare intensity maximizes as the secondary, helical-twisted structure moves away from the active region. This twisted flux tube, associated with the flare triggering, is found to be failed in eruption. The location of the flare activity is found to coincide with the activation site of the helical twisted structures. We conclude that the activation of successive helical twists (especially the second one) in the magnetic flux tubes/ropes plays a crucial role in the energy build-up process and triggering of the M-class solar flare without a coronal mass ejection (CME).

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Stereoscopic Analysis of the 19 May 2007 Erupting Filament

Cited by 96 publications

References 23 publications

3D Evolution of a Filament Disappearance Event Observed by STEREO

3D Evolution of a Filament Disappearance Event Observed by STEREO

Evidence for magnetic flux cancelation leading to an ejective solar eruption observed byHinode,TRACE,STEREO, andSoHO/MDI

Multiwavelength Study of the M8.9/3B Solar Flare from AR NOAA 10960

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