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North/South Hemispheric Periodicities in the > 25 MeV Solar Proton Event Rate During the Rising and Peak Phases of Solar Cycle 24

Citation

Richardson, IG and von Rosenvinge, TT and Cane, HV, North/South Hemispheric Periodicities in the > 25 MeV Solar Proton Event Rate During the Rising and Peak Phases of Solar Cycle 24, Solar Physics, 291, (7) pp. 2117-2134. ISSN 0038-0938 (2016) [Refereed Article]

Copyright Statement

Copyright 2016 Springer Science+Business Media Dordrecht

DOI: doi:10.1007/s11207-016-0948-4

Abstract

We present evidence that > 25 MeV solar proton events show a clustering in time at intervals of about six months that persisted during the rising and peak phases of Solar Cycle 24. This phenomenon is most clearly demonstrated by considering events originating in the northern or southern solar hemispheres separately. We examine how these variations in the solar energetic particle (SEP) event rate are related to other phenomena, such as hemispheric sunspot numbers and areas, rates of coronal mass ejections, and the mean solar magnetic field. Most obviously, the SEP event rate closely follows the sunspot number and area in the same hemisphere. The variations of about six months are associated with features in many of the other parameters we examine, indicating that they are just one signature of the episodic development of Cycle 24. They may be related to periodicities of about 150 days reported in various solar and interplanetary phenomena during previous solar cycles. The clear presence of periodicities of about six months in Cycle 24 that evolve independently in each hemisphere contradicts a scenario suggested by McIntosh et al. (Nature Com.6, 6491, 2015) for the variational timescales of solar magnetism.

Item Details

Item Type:Refereed Article
Keywords:solar energetic particles, solar cycle, sunspot area
Research Division:Physical Sciences
Research Group:Astronomical and Space Sciences
Research Field:Space and Solar Physics
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Physical Sciences
Author:Cane, HV (Dr Hilary Cane)
ID Code:110777
Year Published:2016
Web of Science® Times Cited:3
Deposited By:Mathematics and Physics
Deposited On:2016-08-12
Last Modified:2017-11-01
Downloads:0

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