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The source of the major solar energetic particle events from super active region 11944

Brooks, DH; Yardley, SL; (2021) The source of the major solar energetic particle events from super active region 11944. Science Advances , 7 (10) , Article eabf0068. 10.1126/sciadv.abf0068. Green open access

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Abstract

Shock waves associated with fast coronal mass ejections (CMEs) accelerate solar energetic particles (SEPs) in the long duration, gradual events that pose hazards to crewed spaceflight and near-Earth technological assets, but the source of the CME shock-accelerated plasma is still debated. Here, we use multi-messenger observations from the Heliophysics System Observatory to identify plasma confined at the footpoints of the hot, core loops of active region 11944 as the source of major gradual SEP events in January 2014. We show that the elemental composition signature detected spectroscopically at the footpoints explains the measurements made by particle counting techniques near Earth. Our results localize the elemental fractionation process to the top of the chromosphere. The plasma confined closest to that region, where the coronal magnetic field strength is high (a few hundred Gauss), develops the SEP composition signature. This source material is continually released from magnetic confinement and accelerated as SEPs following M-, C-, and X-class flares.

Type: Article
Title: The source of the major solar energetic particle events from super active region 11944
Open access status: An open access version is available from UCL Discovery
DOI: 10.1126/sciadv.abf0068
Publisher version: https://doi.org/10.1126/sciadv.abf0068
Language: English
Additional information: Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics
URI: https://discovery.ucl.ac.uk/id/eprint/10124307
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