Coronal Magnetic Reconnection Driven by Cme Expansion—the 2011 June 7 Event

Driel-Gesztelyi, L. van; Baker, D.; Török, Tibor; Pariat, É.; Green, L. M.; Williams, David R.; Carlyle, J.; Valori, G.; Démoulin, P.; Kliem, B.; Long, David M.; Matthews, Sarah; Malherbe, Jean-Marie

doi:10.1088/0004-637x/788/1/85

Cited by 57 publications

(36 citation statements)

References 48 publications

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“…One of the most spectacular and best studied solar eruptions of solar cycle 24 occurred on June 7, 2011 (Cheng et al, 2012;Nitta et al, 2013;van Driel-Gesztelyi et al, 2014). The eruption was associated with active region (AR) 11226 (S21, W54).…”

Section: June 7 2011 Eventmentioning

confidence: 99%

The Coronal Analysis of SHocks and Waves (CASHeW) framework

Kozarev

Davey

Kendrick

et al. 2017

J. Space Weather Space Clim.

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-Coronal bright fronts (CBF) are large-scale wavelike disturbances in the solar corona, related to solar eruptions. They are observed (mostly in extreme ultraviolet (EUV) light) as transient bright fronts of finite width, propagating away from the eruption source location. Recent studies of individual solar eruptive events have used EUVobservations of CBFs and metric radio type II burst observations to show the intimate connection between waves in the low corona and coronal mass ejection (CME)-driven shocks. EUV imaging with the atmospheric imaging assembly instrument on the solar dynamics observatory has proven particularly useful for detecting large-scale short-lived CBFs, which, combined with radio and in situ observations, holds great promise for early CME-driven shock characterization capability. This characterization can further be automated, and related to models of particle acceleration to produce estimates of particle fluxes in the corona and in the near Earth environment early in events. We present a framework for the coronal analysis of shocks and waves (CASHeW). It combines analysis of NASA Heliophysics System Observatory data products and relevant data-driven models, into an automated system for the characterization of off-limb coronal waves and shocks and the evaluation of their capability to accelerate solar energetic particles (SEPs). The system utilizes EUV observations and models written in the interactive data language. In addition, it leverages analysis tools from the SolarSoft package of libraries, as well as third party libraries. We have tested the CASHeW framework on a representative list of coronal bright front events. Here we present its features, as well as initial results. With this framework, we hope to contribute to the overall understanding of coronal shock waves, their importance for energetic particle acceleration, as well as to the better ability to forecast SEP events fluxes.

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Section: June 7 2011 Eventmentioning

confidence: 99%

The Coronal Analysis of SHocks and Waves (CASHeW) framework

Kozarev

Davey

Kendrick

et al. 2017

J. Space Weather Space Clim.

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“…The mechanism that releases magnetic energy is known as magnetic reconnection. Observational as well as theoretical aspects of this mechanism have been studied in detail (e.g., Parker 1963;Demoulin et al 1993;Litvinenko & Somov 1993;Yokoyama et al 2001;Aulanier et al 2006;Veronig et al 2006;Su et al 2013;Dudík et al 2014;van Driel-Gesztelyi et al 2014;Li & Zhang 2015).…”

Section: Introductionmentioning

confidence: 99%

Chromospheric evaporation flows and density changes deduced from Hinode/EIS during an M1.6 flare

Gömöry

Veronig

et al. 2016

A&A

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Aims. We study the response of the solar atmosphere during a GOES M1.6 flare using spectroscopic and imaging observations. In particular, we examine the evolution of the mass flows and electron density together with the energy input derived from hard X-ray (HXR) in the context of chromospheric evaporation.Methods. We analyzed high-cadence sit-and-stare observations acquired with the Hinode/EIS spectrometer in the Fe xiii 202.044 Å (log T = 6.2) and Fe xvi 262.980 Å (log T = 6.4) spectral lines to derive temporal variations of the line intensity, Doppler shifts, and electron density during the flare. We combined these data with HXR measurements acquired with RHESSI to derive the energy input to the lower atmosphere by flare-accelerated electrons.Results. During the flare impulsive phase, we observe no significant flows in the cooler Fe xiii line but strong upflows, up to 80-150 km s −1 , in the hotter Fe xvi line. The largest Doppler shifts observed in the Fe xvi line were co-temporal with the sharp intensity peak. The electron density obtained from a Fe xiii line pair ratio exhibited fast increase (within two minutes) from the pre-flare level of 5.01 × 10 9 cm −3 to 3.16 × 10 10 cm −3 during the flare peak. The nonthermal energy flux density deposited from the coronal acceleration site to the lower atmospheric layers during the flare peak was found to be 1.34 × 10 10 erg s −1 cm −2 for a low-energy cut-off that was estimated to be 16 keV. During the decline flare phase, we found a secondary intensity and density peak of lower amplitude that was preceded by upflows of ∼15 km s −1 that were detected in both lines. The flare was also accompanied by a filament eruption that was partly captured by the EIS observations. We derived Doppler velocities of 250-300 km s −1 for the upflowing filament material. Conclusions. The spectroscopic results for the flare peak are consistent with the scenario of explosive chromospheric evaporation, although a comparatively low value of the nonthermal energy flux density was determined for this phase of the flare. This outcome is discussed in the context of recent hydrodynamic simulations. It provides observational evidence that the response of the atmospheric plasma strongly depends on the properties of the electron beams responsible for the heating, in particular the steepness of the energy distribution. The secondary peak of line intensity and electron density detected during the decline phase is interpreted as a signature of flare loops being filled by expanding hot material that is due to chromospheric evaporation.

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“…The spine of a filament consists of dense plasma concentrated around the centre of a longer magnetic flux tube [14][15][16][17][18] , and so the disconnections and reconnections of the filament spine indicate a reconfiguration of magnetic field topology of the filament. Our observations represent a clear example of such reconnection and provide details of the process.…”

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confidence: 99%

Magnetic reconnection between a solar filament and nearby coronal loops

et al. 2016

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Magnetic reconnection, the rearrangement of magnetic field topology, is a fundamental physical process in magnetized plasma systems all over the universe 1,2 . Its process is difficult to be directly observed. Coronal structures, such as coronal loops and filament spines, often sketch the magnetic field geometry and its changes in the solar corona 3 . Here we show a highly suggestive observation of magnetic reconnection between an erupting solar filament and its nearby coronal loops, resulting in changes in connection of the filament. X-type structures form when the erupting filament encounters the loops. The filament becomes straight, and bright current sheets form at the interfaces with the loops. Many plasmoids appear in these current sheets and propagate bi-directionally. The filament disconnects from the current sheets, which gradually disperse and disappear, reconnects to the loops, and becomes redirected to the loop footpoints. This evolution of the filament and the loops suggests successive magnetic reconnection predicted by theories 1 but rarely detected with such clarity in observations. Our results on the formation, evolution, and disappearance of current sheets, confirm three-dimensional magnetic reconnection theory and have implications for the evolution of dissipation regions and the release of magnetic energy for reconnection in many magnetized plasma systems.Magnetic reconnection 1,2 is considered to play an essential role in the rapid release of the magnetic energy and its conversion to other forms (thermal, kinetic and particle) in magnetized plasma systems (such as accretion disks, solar and stellar coronae, planetary magnetospheres, and laboratory plasmas) throughout the universe. It shows the reconfiguration of the magnetic field geometry. In solar physics, numerous theoretical studies of the magnetic reconnection have been undertaken to explain flares 5 , filament eruptions 6 , et al. In two dimensional (2D) models, reconnection occurs at an X-point where anti-parallel magnetic field lines converge and reconnect 1,5,6 . So far, many observations of magnetic reconnection signatures, e.g., cusp-shaped post-flare loops 7 , loop-top hard X-ray source 3,8 , reconnection inflows 3,9 and outflows 3,10,11 , flare supra-arcades downflows 12,13 , current sheets, and plasmoid ejections 11 , have been reported by using remote sensing data. However, to directly observe the details of magnetic reconnection process is difficult, because of the small spatial scale and the fast temporal evolution of the process.A solar filament is a relatively cool and dense plasma structure in the corona suspended above a magnetic polarity inversion line (PIL), with ends rooted in regions with opposite magnetic polarity. Its spine, a narrow ribbon-like structure through the full filament, consists of horizontal and parallel threads 14 when viewed from above. In the region around a filament, the plasma-beta, i.e., the ratio of thermal to magnetic energy density, is below unity. Because of the high electric conductivity, the...

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Coronal Magnetic Reconnection Driven by Cme Expansion—the 2011 June 7 Event

Cited by 57 publications

References 48 publications

The Coronal Analysis of SHocks and Waves (CASHeW) framework

The Coronal Analysis of SHocks and Waves (CASHeW) framework

Chromospheric evaporation flows and density changes deduced from Hinode/EIS during an M1.6 flare

Magnetic reconnection between a solar filament and nearby coronal loops

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