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Solar energetic particle characteristics and their dependence on longitude in solar cycle 24

Cohen, C. M. S. and Mason, G. M. and Mewaldt, R. A. and von Rosenvinge, T. T. (2013) Solar energetic particle characteristics and their dependence on longitude in solar cycle 24. In: Solar Wind 13: Proceedings of the Thirteenth International Solar Wind Conference. AIP Conference Proceedings. No.1539. American Institute of Physics , Melville, NY, pp. 151-154. ISBN 978-0-7354-1163-0.

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In previous solar cycles, most studies examining the longitude dependence of solar energetic particle (SEP) event characteristics (such as composition and spectral hardness) have involved statistical analysis of single-point measurements. With the significant separation between the two STEREO and near-Earth spacecraft during solar cycle 24, these SEP characteristics can be examined simultaneously from multiple vantage points. Using SEP measurements from sensors on STEREO and ACE, we have examined the longitude dependence of the Fe/O abundance ratio at 10 MeV/nuc and the oxygen spectral index for energies above 10 MeV/nuc. Longitudinal patterns were sought that support or refute the scenarios put forth by Tylka et al. and Cane et al. to explain the Fe-enriched large SEP events of cycle 23. Unfortunately few Fe-enriched events have occurred in cycle 24 and their longitudinal behavior is not entirely consistent with either of the proposed scenarios.

Item Type:Book Section
Related URLs:
URLURL TypeDescription
Cohen, C. M. S.0000-0002-0978-8127
Mason, G. M.0000-0003-2169-9618
Mewaldt, R. A.0000-0003-2178-9111
Additional Information:© 2013 AIP Publishing LLC. This work was supported by NASA under grants NNX11A0756, NNX08AI11G and NNX10AQ68G at Caltech, NNX10AT75G at JHUAPL, subcontracts SA2715-26309 from UC Berkeley (NASA contract NAS5-03131) and by NSF grant AGS-1156004 at Caltech and AGS-1156138 at JHUAPL. We thank Nariaki Nitta for useful discussions regarding solar source identifications.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
Subject Keywords:cosmic ray composition, cosmic ray energy spectra, solar cosmic ray particles
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Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2013-20
Series Name:AIP Conference Proceedings
Issue or Number:1539
Classification Code:PACS:; 96.50.Vg; 96.60.Vg
Record Number:CaltechAUTHORS:20130701-130656583
Persistent URL:
Usage Policy:Copyright 2013 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in SOLAR WIND 13: Proceedings of the Thirteenth International Solar Wind Conference and may be found at
ID Code:39166
Deposited By: Tony Diaz
Deposited On:12 Aug 2013 23:12
Last Modified:09 Nov 2021 23:43

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