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Abstract

We analyze one of the first solar energetic particle (SEP) events of solar cycle 24 observed at widely separated spacecraft in order to assess the reliability of models currently used to determine the connectivity between the sources of SEPs at the Sun and spacecraft in the inner heliosphere. This SEP event was observed on 2010 August 14 by near-Earth spacecraft, STEREO-A (∼80° west of Earth) and STEREO-B (∼72° east of Earth). In contrast to near-Earth spacecraft, the footpoints of the nominal magnetic field lines connecting STEREO-A and STEREO-B with the Sun were separated from the region where the parent fast halo coronal mass ejection (CME) originated by ∼88° and ∼47° in longitude, respectively. We discuss the properties of the phenomena associated with this solar eruption. Extreme ultraviolet and white-light images are used to specify the extent of the associated CME-driven coronal shock. We then assess whether the SEPs observed at the three heliospheric locations were accelerated by this shock or whether transport mechanisms in the corona and/or interplanetary space provide an alternative explanation for the arrival of particles at the poorly connected spacecraft. A possible scenario consistent with the observations indicates that the observation of SEPs at STEREO-B and near Earth resulted from particle injection by the CME shock onto the field lines connecting to these spacecraft, whereas SEPs reached STEREO-A mostly via cross-field diffusive transport processes. The successes, limitations, and uncertainties of the methods used to resolve the connection between the acceleration sites of SEPs and the spacecraft are evaluated.

Item Type:	Article
Authors/Creators:	Lario, D and Kwon, RY and Richardson, IG and Raouafi, NE and Thompson, BJ and Rosenvinge, TTV and Mays, ML and Makela, PA and Xie, H and Bain, HM and Zhang, M and Zhao, L and Cane, HV and Papaioannou, A and Thakur, N and Riley, P
Keywords:	solar energetic particles, CMEs, shocks, acceleration of particles, sun activity, coronal mass ejections, heliosphere, magnetic fields, particle emission
Journal or Publication Title:	Astrophysical Journal
Publisher:	Univ Chicago Press
ISSN:	0004-637X
DOI / ID Number:	https://doi.org/10.3847/1538-4357/aa63e4
Copyright Information:	Copyright 2017 The American Astronomical Society
Item Statistics:	View statistics for this item

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