AffiliationUniv Arizona, Lunar & Planetary Lab
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PublisherIOP PUBLISHING LTD
CitationXin Wang et al 2019 ApJ 885 66
RightsCopyright © 2019. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractGround-level enhancement (GLE) events are often associated with large gradual solar events such as fast coronal mass ejections (CMEs), but not all fast CMEs lead to GLE events. Is there a type of coordinated CME that could produce GLEs with larger intensity and higher energies than those in the normal fast isolated CMEs? Here we propose a twin-shock scenario driven by the twin CME coordinately, in which the posterior shock catches up with the preceding shock and has a pileup collision. In the present study, we chose the first GLE event of the solar cycle 24 occurring on 2012 May 17 as an example to investigate the probable association with the twin-shock scenario. We use a dynamic Monte Carlo method to examine the energy spectrum with relevance to the GLE event. In the twin-shock scenario, the seed energetic particles produced by the normal preceding shock can be injected into the posterior shock for reacceleration efficiently. As a result, we obtain the detailed energy spectrum of the solar energetic particles (SEPs) with different behaviors at the related episodes of the twin-shock evolution. Therefore, we predict that the pileup collision of the twin shock would dominate a concave energy spectral slope in the 2012 May 17 SEP event.
VersionFinal published version
SponsorsXinjiang Natural Science Foundation [2019D01A100]; Xinjiang Heaven Lake Hundred-Talent Program; NSFC, National Natural Science Foundation of China ; CAS Key Laboratory of Solar Activity, National Astronomical Observatories; Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education; China Scholarship Council (CSC), China Scholarship Council; Supercomputer Center of University of Arizona