Saddle-shaped solar flare arcades

Abstract

Arcades of flare loops form as a consequence of magnetic reconnection powering solar flares and eruptions. We analyse the morphology and evolution of flare arcades that formed during five well-known eruptive flares. We show that the arcades have a common saddle-like shape. The saddles occur despite the fact that the flares were of different classes (C to X), occurred in different magnetic environments, and were observed in various projections. The saddles are related to the presence of longer, relatively-higher, and inclined flare loops, consistently observed at the ends of the arcades, which we term `cantles'. Our observations indicate that cantles typically join straight portions of flare ribbons with hooked extensions of the conjugate ribbons. The origin of the cantles is investigated in stereoscopic observations of the 2011 May 9 eruptive flare carried out by the Atmospheric Imaging Assembly (AIA) and Extreme Ultraviolet Imager (EUVI). The mutual separation of the instruments led to ideal observational conditions allowing for simultaneous analysis of the evolving cantle and the underlying ribbon hook. Based on our analysis we suggest that the formation of one of the cantles can be explained by magnetic reconnection between the erupting structure and its overlying arcades. We propose that the morphology of flare arcades can provide information about the reconnection geometries in which the individual flare loops originate.

9 pages, 5 figures

References in corpus (29)

• An Observational Overview of Solar Flares
• Observation of An Evolving Magnetic Flux Rope Prior To and During A Solar Eruption
• The standard flare model in three dimensions III. Slip-running reconnection properties
• Sun-to-Earth MHD Simulation of the 14 July 2000 "Bastille Day" Eruption
• Reconnection Outflows and Current Sheet Observed with Hinode/XRT in the 2008 April 9 "Cartwheel CME" Flare
• Spectroscopic Observations of Current Sheet Formation and Evolution
• Simultaneous observation of a flux rope eruption and magnetic reconnection during an X-class solar flare
• Re-interpretation of Supra-Arcade Downflows in Solar Flares
• Successive X-class flares and coronal mass ejections driven by shearing motion and sunspot rotation in active region NOAA 12673
• Drifting of the line-tied footpoints of CME flux-ropes
• Magnetohydrodynamic Simulation of the X2.2 Solar Flare on 2011 February 15: I. Comparison with the Observations
• Self-Consistent MHD Modeling of a Coronal Mass Ejection, Coronal Dimming, and a Giant Cusp-Shaped Arcade Formation
• Magnetohydrodynamic Simulation of the X2.2 Solar Flare on 2011 February 15: II. Dynamics Connecting the Solar Flare and the Coronal Mass Ejection
• Coronal magnetic reconnection driven by CME expansion -- the 2011 June 7 event
• Microwave Spectral Imaging of an Erupting Magnetic Flux Rope: Implications for the Standard Solar Flare Model in Three Dimensions
• Elongation of Flare Ribbons
• Broad Non-Gaussian Fe XXIV Line Profiles in the Impulsive Phase of the 2017 September 10 X8.3 class Flare Observed by Hinode/EIS
• 3D magnetic reconnection and its application to solar flares
• Observations of Reconnecting Flare Loops with the Atmospheric Imaging Assembly (AIA)
• Flux cancellation and the evolution of the eruptive filament of 2011 June 7
• The Nature of CME-Flare Associated Coronal Dimming
• Observations of a Footpoint Drift of an Erupting Flux Rope
• Observational Analysis on the Early Evolution of a CME Flux-rope: Pre-flare reconnection and Flux-rope's Footpoint Drift
• Thermodynamical Evolution of Supra-Arcade Downflows
• Observation of all pre- and post-reconnection structures involved in three-dimensional reconnection geometries in solar eruptions
• Continuous Null-Point Magnetic Reconnection Builds Up a Torus Unstable Magnetic Flux Rope Triggering the X9.3 Flare in Solar Active Region~12673
• On the Cause of Supra-Arcade Downflows in Solar Flares
• Manifestations of three dimensional magnetic reconnection in an eruption of a quiescent filament: \\ Filament strands turning to flare loops
• Can Sub-photospheric Magnetic Reconnection Change the Elemental Composition in the Solar Corona?

Cited by in corpus (3)

• SCSS-Net: Solar Corona Structures Segmentation by Deep Learning
• Filament Leg--Leg Reconnection as a Source of Prominent Supra-Arcade Downflows
• Spectroscopic investigations of a filament reconnecting with coronal loops during a two-ribbon solar flare