The surge-like eruption of a miniature filament associated with circular flare ribbon

Context. Quasi-periodic pulsations (QPPs) are a common feature of solar flares, but there has previously been a lack of observational evidence to support any of the theoretical models that might explain the origin of these QPPs. Aims. We aimed to determine if there are any relationships between the QPP period and other properties of the flaring region, using a previously assembled sample of flares with QPPs. If any relationships exist, then these can be compared with scaling laws for the theoretical QPP mechanisms. Methods. To obtain the flaring region properties, we made use of the Atmospheric Imaging Assembly (AIA) 1600 Å and Helioseismic and Magnetic Imager (HMI) data. The flare ribbons are visible in AIA 1600 Å images, and the positive and negative magnetic polarity ribbons can be distinguished and the magnetic properties determined in the HMI magnetograms. The ribbon properties calculated in this study were the ribbon separation distance, area, total unsigned magnetic flux, and average magnetic field strength. Only the flares that occurred within ±60° of the solar disc centre were included, which meant a sample of 20 flares with 22 QPP signals. Results. Positive correlations were found between the QPP period and the ribbon properties. The strongest correlations were with the separation distance and magnetic flux. Because these ribbon properties also correlate with the flare duration and because the relationship between the QPP period and flare duration may be influenced by observational bias, we also made use of simulated data to determine whether artificial correlations were introduced. These simulations show that although QPPs cannot be detected for certain combinations of QPP period and flare duration, this does not introduce an apparent correlation. Conclusions. There is evidence of relationships between the QPP period and flare ribbon properties, and in the future, the derived scaling laws between these properties can be compared to equivalent scaling laws for theoretical QPP mechanisms.

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New Evidence of Chromospheric Evaporation

International Astronomical Union Colloquium ◽

10.1017/s0252921100047990 ◽

1998 ◽

Vol 167 ◽

pp. 397-400 ◽

Cited By ~ 1

Author(s):

J. Kašparová ◽

P. Kotrč ◽

P. Heinzel ◽

I.F. Nikulin ◽

P. Rudawy

Keyword(s):

Astronomical Institute ◽

Gradual Phase ◽

Chromospheric Evaporation ◽

Sternberg Astronomical Institute ◽

Blue Wing ◽

Flare Ribbon ◽

New Evidence ◽

Flare Model

AbstractHα spectra obtained at Sternberg Astronomical Institute in Moscow during the gradual phase of the flare on May 16, 1981 are analysed. The flare-ribbon profiles show a red asymmetry of the emission peaks, and we interpret this as an absorption in the blue wing of the profile due to expected upflows. We demonstrate a good correlation between the observed Hα profiles and those computed with the flare model Fl and upflows reaching 10 km s−1.

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A Technique for Automated Determination of Flare Ribbon Separation and Energy Release

Solar Physics ◽

10.1007/s11207-009-9488-5 ◽

2010 ◽

Vol 262 (2) ◽

pp. 337-353 ◽

Cited By ~ 10

Author(s):

R. A. Maurya ◽

A. Ambastha

Keyword(s):

Energy Release ◽

Flare Ribbon ◽

Automated Determination

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Spectroscopic diagnostics of electron density in a flare ribbon by oxygen IV lines using Non-Maxwellian distribution

Spectroscopy Letters ◽

10.1080/00387010.2019.1681460 ◽

2019 ◽

Vol 52 (10) ◽

pp. 612-621

Author(s):

Jian He ◽

Qingguo Zhang

Keyword(s):

Electron Density ◽

Maxwellian Distribution ◽

Spectroscopic Diagnostics ◽

Flare Ribbon

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QUASI-PERIODIC FLUCTUATIONS AND CHROMOSPHERIC EVAPORATION IN A SOLAR FLARE RIBBON OBSERVED BYHINODE/EIS,IRIS, ANDRHESSI

The Astrophysical Journal ◽

10.3847/0004-637x/830/2/101 ◽

2016 ◽

Vol 830 (2) ◽

pp. 101 ◽

Cited By ~ 21

Author(s):

Jeffrey W. Brosius ◽

Adrian N. Daw ◽

Andrew R. Inglis

Keyword(s):

Solar Flare ◽

Chromospheric Evaporation ◽

Periodic Fluctuations ◽

Flare Ribbon

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Fast degradation of the circular flare ribbon on 2014 August 24

Astronomy and Astrophysics ◽

10.1051/0004-6361/202038072 ◽

2020 ◽

Vol 636 ◽

pp. L11

Author(s):

Q. M. Zhang ◽

S. H. Yang ◽

T. Li ◽

Y. J. Hou ◽

Y. Li

Keyword(s):

Extreme Ultraviolet ◽

Null Point ◽

Second Phase ◽

Solar Dynamics Observatory ◽

X Ray ◽

Counterclockwise Direction ◽

Solar Dynamics ◽

Flare Ribbon ◽

Two Phases ◽

Two Jets

Context. The separation and elongation motions of solar flare ribbons have extensively been investigated. The degradation and disappearance of ribbons have rarely been explored. Aims. We report our multiwavelength observations of a C5.5 circular-ribbon flare associated with two jets (jet1 and jet2) on 2014 August 24, focusing on the fast degradation of the outer circular ribbon (CR). Methods. The flare was observed in ultraviolet (UV) and extreme-ultraviolet (EUV) wavelengths by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory spacecraft. Soft X-ray fluxes of the flare in 0.5−4 and 1−8 Å were recorded by the GOES spacecraft. Results. The flare, consisting of a short inner ribbon (IR) and outer CR, was triggered by the eruption of a minifilament. The brightness of IR and outer CR reached their maxima simultaneously at ∼04:58 UT in all AIA wavelengths. Subsequently, the short eastern part of the CR faded out quickly in 1600 Å but only gradually in EUV wavelengths. The long western part of the CR degraded in the counterclockwise direction and decelerated. The degradation was distinctly divided into two phases: phase I with faster apparent speeds (58−69 km s−1), and phase II with slower apparent speeds (29−35 km s−1). The second phase stopped at ∼05:10 UT when the western CR disappeared entirely. In addition to the outward propagation of jet1, the jet spire experienced untwisting motion in the counterclockwise direction during 04:55−05:00 UT. Conclusions. We conclude that the event can be explained by the breakout jet model. The coherent brightenings of the IR and CR at ∼04:58 UT may result from the impulsive interchange reconnection near the null point, whereas sub-Alfvénic slipping motion of the western CR in the counterclockwise direction indicates the occurrence of slipping magnetic reconnection. Another possible explanation of the quick disappearance of the hot loops that are connected to the western CR is that they are simply reconnected sequentially without the need for significant slippage after the null-point reconnection.

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