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Article Dans Une Revue Solar Physics Année : 2010

Pre-Flare Flows in the Corona

Résumé

Solar flares take place in regions of strong magnetic fields and are generally accepted to be the result of a resistive instability leading to magnetic reconnection. When new flux emerges into a pre-existing active region it can act as a flare and coronal mass ejection trigger. In this study we observed active region 10955 after the emergence of small-scale additional flux at the magnetic inversion line. We found that flaring began when additional positive flux levels exceeded 1.38×1020 Mx (maxwell), approximately 7 h after the initial flux emergence. We focussed on the pre-flare activity of one B-class flare that occurred on the following day. The earliest indication of activity was a rise in the non-thermal velocity one hour before the flare. 40 min before flaring began, brightenings and pre-flare flows were observed along two loop systems in the corona, involving the new flux and the pre-existing active region loops. We discuss the possibility that reconnection between the new flux and pre-existing loops before the flare drives the flows by either generating slow mode magnetoacoustic waves or a pressure gradient between the newly reconnected loops. The subsequent B-class flare originated from fast reconnection of the same loop systems as the pre-flare flows.

Dates et versions

hal-03729575 , version 1 (20-07-2022)

Identifiants

Citer

A. J. Wallace, Louise K. Harra, Lidia van Driel-Gesztelyi, Lucie M. Green, Sarah A. Matthews. Pre-Flare Flows in the Corona. Solar Physics, 2010, 267, pp.361-375. ⟨10.1007/s11207-010-9661-x⟩. ⟨hal-03729575⟩
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