Eruption of a Kink-unstable Filament in NOAA Active Region 10696

Williams, David R.; Török, Tibor; Démoulin, P.; Driel-Gesztelyi, L. van; Kliem, B.

doi:10.1086/432910

Cited by 185 publications

(163 citation statements)

References 19 publications

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“…The event on 2004 November 10 (08N 49W) has been reported previously by Williams et al (2005), who observed a highly-localised preflare brightening in TRACE 1600 Å images at 01:52 UT, ∼7 min prior to the flare onset ( Fig. A.2).…”

Section: November 10 (Event 4: On-disk)supporting

confidence: 71%

“…However, at present, we cannot exclude an external tether-cutting (or "breakout") scenario, when precursor HXR brightenings were clearly observed above the loop-top high in the corona (events 5 and 6). One filament eruption (event 4) suggested that internal tether-cutting reconnection may be followed closely by external tether-cutting reconnection, with the magnetic tethers being weakened first at low altitudes, and then later at greater altitudes above the filament (Williams et al 2005). …”

Section: Discussionmentioning

confidence: 99%

“…A.2, bottom right panel) is observed along the PIL, within 30 of the preflare emission. Williams et al (2005) found that an exponential function fitted the height-time profile of the erupting filament, suggesting an MHD kink instability trigger. They argue that the filament prior to the eruption was highly twisted, which would also point to the MHD kink instability as an eruption driver.…”

Section: November 10 (Event 4: On-disk)mentioning

confidence: 90%

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X-ray precursors to flares and filament eruptions

Chifor¹,

Tripathi²,

Mason³

et al. 2007

A&A

103

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Aims. To study preflare X-ray brightenings as diagnostics of the destabilisation of flare-associated erupting filaments/prominences. Methods. We combine new observations from the Transition Region and Coronal Explorer (TRACE) and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI), as well as revisit events reported in the literature to date, in order to scrutinise the preflare activity during eight flare-associated filament eruptions. Results. The preflare activity occurs in the form of discrete, localised X-ray brightenings observed between 2 and 50 min before the impulsive phase of the flare and filament acceleration. These transient preflare brightenings are situated on or near (within 10 of) the polarity inversion line (PIL), coincident with emerging and/or canceling magnetic flux. The filaments begin to rise from the location of the preflare brightenings. In five out of eight events, the preflare brightenings were observed beneath the filament channel, close to the filament footpoint first observed to rise. Both thermal and nonthermal hard X-ray emissions during the preflare enhancement were detected with RHESSI, suggesting that both plasma heating and electron acceleration occurred at this time. The main energy release during the impulsive phase of the flare is observed close to (within 50 of) the preflare brightenings. The fast-rise phase of the filament eruption starts at the same time as the onset of the main flare or up to 5 min later. Conclusions. The preflare brightenings are precursors to the flare and filament eruption. These precursors represent distinct, localised instances of energy release, rather than a gradual energy release prior to the main flare. The X-ray precursors represent clearly observable signatures in the early stages of the eruption. Together with the timing of the filament fast-rise at or after the main flare onset, the X-ray precursors provide evidence for a tether-cutting mechanism initially manifested as localised magnetic reconnection being a common trigger for both flare emission and filament eruption.

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Section: November 10 (Event 4: On-disk)supporting

confidence: 71%

Section: Discussionmentioning

confidence: 99%

Section: November 10 (Event 4: On-disk)mentioning

confidence: 90%

See 1 more Smart Citation

X-ray precursors to flares and filament eruptions

Chifor¹,

Tripathi²,

Mason³

et al. 2007

A&A

103

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show abstract

“…Observations have indicated that newly emerging flux can interact with a pre-existing structure and destabilize it, leading to its dynamical rising motion across the solar atmosphere (e.g. Feynman & Martin 1995;Wang & Sheeley 1999;Williams et al 2005). On the other hand, an AR can create its own "eruptions", aided and incited by the pre-existing coronal magnetic field (e.g.…”

Section: Introductionmentioning

confidence: 99%

Magnetic flux emergence: a precursor of solar plasma expulsion

Archontis

Hood

2012

A&A

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Aims. We model the emergence of magnetized plasma from the top of the convection zone to the lower corona. We investigate the eruption of coronal flux ropes above emerging flux regions. Methods. We performed three-dimensional numerical experiments in which the time-dependent and resistive equations of MHD are solved self-consistently, using the Lare3D code. Results. A subphotospheric magnetic flux tube rises from the convectively unstable layer into the solar surface, followed by the formation and eruption of a new flux rope into the corona. Firstly, we examined the case where the corona is field-free. The expansion of the emerging field forms an envelope sheath that surrounds the newly formed flux rope. The erupting ropes are confined by the envelope field. The eruptions are driven by the gradient of the gas pressure and the tension of fieldlines that reconnect within the emerging flux region. The amount of the initial twist of the emerging field and the dense plasma that is lifted up, determine the heighttime profile of the erupting ropes. Secondly, we examined the case of emergence into a pre-existing magnetic field in the upper solar atmosphere. A variety of different ambient field configurations was used in the experiments. External reconnection between the emerging and the pre-existing field may result in the removal of sufficient flux from the interacting fields and the full ejection of the flux ropes. Conclusions. The results indicate that the relative contact angle of the interacting flux systems and their field strengths are crucial parameters that ultimately affect the evolution of the eruption of the rope into the higher solar atmosphere. One important result is that for any contact angle that favors reconnection, ejective eruptions occur earlier when the ambient field is relatively strong. In many cases, the erupting plasma adopts an S-like configuration. The sigmoidal structure accelerates during the fast eruption of the rope. The acceleration is enhanced by the external and internal reconnection of fieldlines during the rising motion of the rope. A key result is that in the reconnection-favored cases, the flux ropes experience ejective eruptions when the envelope flux is reduced (owing to removal by external reconnection) below that of the erupting flux rope. If the envelope flux stays higher than the erupting flux, the magnetic flux rope remains confined by the envelope field.

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“…However, we do not have sufficient understanding and observational signature of the twisted flux ropes and their evolution from the sub-photospheric level into the corona. There are a few observational signatures related to the generation of the twist in the solar filaments, which causes the disruption of their stable magnetic field configuration and generates solar eruptive events (e.g., Liu and Alexander, 2009;Williams et al, 2005 and references cited there). Rust and LaBonte (2005) have also found evidence of sigmoids in the solar corona which were governed and energized by the magnetic twist, without any large-scale destabilization of magnetic fields and associated eruptions from the Sun.…”

Section: Introductionmentioning

confidence: 99%

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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Eruption of a Kink-unstable Filament in NOAA Active Region 10696

Cited by 185 publications

References 19 publications

X-ray precursors to flares and filament eruptions

X-ray precursors to flares and filament eruptions

Magnetic flux emergence: a precursor of solar plasma expulsion

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

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