Birth and evolution of a dense coronal loop in a complex flare region

Bone, L., Brown, J.C., Fletcher, L. , Veronig, A. and White, S. (2007) Birth and evolution of a dense coronal loop in a complex flare region. Astronomy and Astrophysics, 466(1), pp. 339-346. (doi: 10.1051/0004-6361:20065129)

Abstract

<p><b>Context:</b> During the 14th/15th of April 2002, several flares occurred in NOAA active region complex 9893/9910. Two of these were previously interpreted as having anomalously high coronal column densities.</p> <p><b>Aims:</b> We develop a scenario using multiwavelength observations to explain the high coronal column density (1020 cm-2) present at the onset of the 14th April 2002 M3.7 hard X-ray event.</p> <p><b>Methods:</b> Prior to this event a series of flares occurred in close temporal and spatial proximity. We observe the sequence of flares in a multiwavelength regime from radio to hard X-rays. This allows us to study the particle acceleration and plasma evaporation in these events.</p> <p><b>Results:</b> The observations of these flares lead us to propose a sequence of reconnections between multiple systems of loops in a 3 dimensional field geometry. We suggest that the dense loops in the M3.7 event can be explained as being already filled with plasma from the earlier events; these loops then themselves become unstable or reconnect leading to particle acceleration into an overdense coronal environment. We explore the possibility that a high-beta disruption is behind the instability of these dense loops, leading to the 14th April 2002 M3.7 event and the observation of hard X-rays in the corona at energies up to ≈ 50 keV.</p>

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Fletcher, Professor Lyndsay and Brown, Professor John
• Authors: Bone, L., Brown, J.C., Fletcher, L., Veronig, A., and White, S.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Astronomy and Astrophysics
• Publisher: EDP Sciences
• ISSN: 0004-6361
• ISSN (Online): 1432-0746
• Copyright Holders: Copyright © 2007 EDP Sciences
• First Published: First published in Astronomy and Astrophysics 466(1):339-346
• Publisher Policy: Reproduced in accordance with the copyright policy of the publisher