Multiwavelength Study of Flow Fields in Flaring Super Active Region NOAA 10486

Deng, Na; Xu, Yan; Guo, Yang; Cao, Wenda; Liu, Chang; Rimmelé, Thomas; Wang, Haimin; Denker, C.

doi:10.1086/503600

Cited by 50 publications

(52 citation statements)

References 43 publications

(49 reference statements)

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“…It is commonly accepted that a solar flare suddenly releases magnetic free energy that is stored in the form of a stressed magnetic topology (e.g., Deng et al 2006). Magnetic flux emergence and cancellation may play an important role in injecting magnetic energy through the photosphere into the corona.…”

Section: Discussionmentioning

confidence: 99%

“…Solar flares are powered by the energy stored in the stressed magnetic field; strong flares tend to occur in the vicinity of magnetic neutral lines where the field gradients are strong and the horizontal components are highly sheared (e.g., Harvey & Harvey 1976;Wang et al 1994Wang et al , 2002Deng et al 2006). The movement of magnetic footpoints by photospheric flows can lead to the destabilization of the magnetic field and hence to flares by increasing the length of the field lines in the corona (e.g., Somov et al 2002).…”

Section: Introductionmentioning

confidence: 99%

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Interaction between a Fast Rotating Sunspot and Ephemeral Regions as the Origin of the Major Solar Event on 2006 December 13

Zhang

Song

2007

ApJ

109

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The major solar event on 2006 December 13 is characterized by the approximately simultaneous occurrence of a heap of hot ejecta, a great two-ribbon flare, and an extended Earth-directed coronal mass ejection. We examine the magnetic field and sunspot evolution in NOAA AR 10930, the source region of the event, while it transited the solar disk center from December 10 to 13. We find that the obvious changes in the active region associated with the event are the development of magnetic shear, the appearance of ephemeral regions, and fast rotation of a smaller sunspot. Around the area of the magnetic neutral line of the active region, interaction between the fast rotating sunspot and the ephemeral regions triggers continual brightening and finally the major flare. This indicates that only after the sunspot rotates up to 200Њ does the major event take place. The sunspot rotates at least 240Њ about its center, the largest sunspot rotation angle that has been reported.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Interaction between a Fast Rotating Sunspot and Ephemeral Regions as the Origin of the Major Solar Event on 2006 December 13

Zhang

Song

2007

ApJ

109

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“…It possessed curved penumbral filaments pointing eastwards, which are indicative of twisted magnetic field lines. These non-radial penumbral filaments are frequently observed in flaring sunspots with horizontal shear flows (Denker et al 2007;Deng et al 2006). On November 19, the faint light-bridges had disappeared and the penumbra had vanished leaving only a single pore, which was filled with conglomerates of umbral dots.…”

Section: Photospheric Evolutionmentioning

confidence: 96%

Horizontal flow fields observed in Hinode G-band images

Verma

Balthasar

Deng

et al. 2012

A&A

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Context. Generation and dissipation of magnetic fields is a fundamental physical process on the Sun. In comparison to flux emergence and the initial stages of sunspot formation, the demise of sunspots still lacks a comprehensive description. Aims. The evolution of sunspots is most commonly discussed in terms of their intensity and magnetic field. Here, we present additional information about the three-dimensional flow field in the vicinity of sunspots towards the end of their existence. Methods. We present a subset of multi-wavelengths observations obtained with the Japanese Hinode mission, the Solar Dynamics Observatory (SDO), and the Vacuum Tower Telescope (VTT) at Observatorio del Teide, Tenerife, Spain during the time period 2010 November 18−23. Horizontal proper motions were derived from G-band and Ca ii H images, whereas line-of-sight velocities were extracted from VTT echelle Hα λ656.28 nm spectra and Fe i λ630.25 nm spectral data of the Hinode/Spectro-Polarimeter, which also provided three-dimensional magnetic field information. The Helioseismic and Magnetic Imager on board SDO provided continuum images and line-of-sight magnetograms, in addition to the high-resolution observations for the entire disk passage of the active region. Results. We perform a quantitative study of photospheric and chromospheric flow fields in and around decaying sunspots. In one of the trailing sunspots of active region NOAA 11126, we observe moat flow and moving magnetic features (MMFs), even after its penumbra had decayed. We also detect a superpenumbral structure around this pore. We find that MMFs follow well-defined, radial paths from the spot all the way to the border of a supergranular cell surrounding the spot. In contrast, flux emergence near the other sunspot prevents the establishment of similar well ordered flow patterns, which could be discerned around a tiny pore of merely 2 Mm diameter. After the disappearance of the sunspots/pores, a coherent patch of abnormal granulation remained at their location, which was characterized by more uniform horizontal proper motions, low divergence values, and smaller photospheric Doppler velocities. This region, thus, differs significantly from granulation and other areas covered by G-band bright points. We conclude that this peculiar flow pattern is a signature of sunspot decay and the dispersal of magnetic flux.

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“…The first is a classical LCT code (CLCT) that is the Lockheed Martin's Solar and Astrophysical Laboratory's version based on the original works of November & Simon (1988). This method was used before e.g., by Deng et al (2006Deng et al ( , 2007. The second method is Fourier local correlation tracking (FLCT) presented by Fisher & Welsch (2008).…”

Section: Observations and Data Reductionmentioning

confidence: 99%

The three-dimensional structure of sunspots

Balthasar¹,

Muglach²

2010

A&A

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Aims. Many sunspots are surrounded by a radial outflow called the moat flow. We investigate the moat flow at two different heights of the solar atmosphere for a sunspot whose magnetic properties were reported in the first paper of this series. Methods. We use two simultaneous time series taken with the Transition Region And Coronal Explorer (TRACE) in white light and in the UV at 170 nm. The field-of-view is centered on the small sunspot NOAA 10886 located near disk center. Horizontal velocities are derived by applying two different local correlation tracking techniques. Results. Outflows are found everywhere in the moat. In the inner moat, the velocities from the UV series are larger than those from white light, whereas in the outer part of the moat we find the converse result. Conclusions. The results imply that the white light velocities represent a general outflow of the quiet sun plasma in the moat, while UV velocities are dominated by small bright points that move faster than the general plasma flow.

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Multiwavelength Study of Flow Fields in Flaring Super Active Region NOAA 10486

Cited by 50 publications

References 43 publications

Interaction between a Fast Rotating Sunspot and Ephemeral Regions as the Origin of the Major Solar Event on 2006 December 13

Interaction between a Fast Rotating Sunspot and Ephemeral Regions as the Origin of the Major Solar Event on 2006 December 13

Horizontal flow fields observed in Hinode G-band images

The three-dimensional structure of sunspots

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