A1 Refereed original research article in a scientific journal
On the Role of Coronal Shocks for Accelerating Solar Energetic Electrons
Authors: Dresing Nina, Kouloumvakos Athanasios, Vainio Rami, Rouillard Alexis
Publisher: IOP Publishing Ltd
Publication year: 2022
Journal: Astrophysical Journal Letters
Journal name in source: ASTROPHYSICAL JOURNAL LETTERS
Journal acronym: ASTROPHYS J LETT
Article number: L21
Volume: 925
Number of pages: 7
ISSN: 2041-8205
DOI: https://doi.org/10.3847/2041-8213/ac4ca7
Web address : https://doi.org/10.3847/2041-8213/ac4ca7
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/174818419
We study the role of coronal mass ejection (CME) driven shocks in the acceleration of solar energetic electrons. Using observations by the two STEREO spacecraft, we correlate electron peak intensities of solar energetic particle events measured in situ with various parameters of the associated coronal shocks. These shock parameters were derived by combining 3D shock reconstructions with global modeling of the corona. This modeling technique provides also shock properties in the specific shock regions that are magnetically connected to the two STEREO spacecraft. We find significant correlations between the peak intensities and the Mach number of the shock with correlation coefficients of about 0.7, which are similar for electrons at similar to 1 MeV and protons at >60 MeV. Lower-energy electrons with <100 keV show a smaller correlation coefficient of 0.47. The causal relationship between electron intensities and the shock properties is supported by the vanishing correlations when peak intensities at STEREO A are related with the Alfvenic Mach number at the magnetic footpoint of STEREO B and vice versa, which yields correlation coefficients of 0.03 and -0.13 for similar to 1 MeV and <100 keV electron peak intensities, respectively. We conclude that the high-energy electrons are accelerated mainly by the shock, while the low-energy electrons are likely produced by a mixture of flare and shock-related acceleration processes.
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