Long, DM;
Reid, HAS;
Valori, G;
O'Kane, J;
(2021)
Localized Acceleration of Energetic Particles by a Weak Shock in the Solar Corona.
The Astrophysical Journal
, 921
(1)
, Article 61. 10.3847/1538-4357/ac1cdf.
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Abstract
Globally-propagating shocks in the solar corona have long been studied to quantify their involvement in the acceleration of energetic particles. However, this work has tended to focus on large events associated with strong solar flares and fast coronal mass ejections (CMEs), where the waves are sufficiently fast to easily accelerate particles to high energies. Here we present observations of particle acceleration associated with a global wave event which occurred on 1 October 2011. Using differential emission measure analysis, the global shock wave was found to be incredibly weak, with an Alfv\'en Mach number of ~1.008-1.013. Despite this, spatially-resolved type III radio emission was observed by the Nan\c{c}ay RadioHeliograph at distinct locations near the shock front, suggesting localised acceleration of energetic electrons. Further investigation using a magnetic field extrapolation identified a fan structure beneath a magnetic null located above the source active region, with the erupting CME contained within this topological feature. We propose that a reconfiguration of the coronal magnetic field driven by the erupting CME enabled the weak shock to accelerate particles along field lines initially contained within the fan and subsequently opened into the heliosphere, producing the observed type III emission. These results suggest that even weak global shocks in the solar corona can accelerate energetic particles via reconfiguration of the surrounding magnetic field.
| Type: | Article |
|---|---|
| Title: | Localized Acceleration of Energetic Particles by a Weak Shock in the Solar Corona |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.3847/1538-4357/ac1cdf |
| Publisher version: | https://doi.org/10.3847/1538-4357/ac1cdf |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher's terms and conditions. |
| Keywords: | astro-ph.SR, astro-ph.SR |
| 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-pp.ucl.ac.uk/id/eprint/10137515 |
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