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dc.contributor.authorMoraal, H.en_US
dc.contributor.authorStoker, P.H.en_US
dc.date.accessioned2012-02-29T09:51:50Z
dc.date.available2012-02-29T09:51:50Z
dc.date.issued2010en_US
dc.identifier.citationMoraal, H. & Stoker, P.H. 2010. Long-term neutron monitor observations and the 2009 cosmic ray maximum. Journal of geophysical research. Space physics, 115: Article no A12109. [http://dx.doi.org/10.1029/2010JA015413]en_US
dc.identifier.issn0148-0227en_US
dc.identifier.issn2156-2202 (Online)en_US
dc.identifier.urihttp://hdl.handle.net/10394/6045
dc.identifier.urihttp://dx.doi.org/10.1029/2010JA015413
dc.identifier.urihttp://onlinelibrary.wiley.com/doi/10.1029/2010JA015413/epdf
dc.description.abstractThe solar minimum of 2009 was characterized by a prolonged increase toward the maximum cosmic ray intensity, which was higher than it was during the maxima of 22 and 44 years ago. In the previous two so-called qA <0 (solar dipole moment facing South) magnetic cycles, these increases were more sharply peaked than in 2009. The observations of the Sanae, Hermanus, Potchefstroom, and Tsumeb neutron monitors are used to investigate this behavior in terms of propagation conditions due to solar activity, the heliospheric magnetic field, and the profile of the wavy current sheet in the field. This 2009 cosmic ray maximum can only be understood after an investigation of the long-term cosmic ray record. This study is augmented by observations of eight other neutron monitors. During 2009, solar activity parameters were significantly different from previous solar minima: The sun was much quieter, and the the heliospheric magnetic field was more than 20% weaker than during other recent minima. Both of these parameters imply a higher cosmic ray diffusion coefficient, which provides a natural explanation for both the higher galactic cosmic ray intensities that were observed and the absence of such an effect for anomalous cosmic rays
dc.publisherAmerican Geophysical Unionen_US
dc.subjectCosmic rays
dc.titleLong-term neutron monitor observations and the 2009 cosmic ray maximumen_US
dc.contributor.researchID10163581 - Stoker, Pieter Helenius
dc.contributor.researchID10178422 - Moraal, Harm


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