Long-Term Cosmic Ray Variability and the CME-Index

The cosmic ray modulation in relation to solar activity indices and heliospheric parameters during the period January 1996–October 2011, covering the solar cycle 23 and the ascending phase of solar cycle 24, is studied. The new perspective of this contribution is that the CME-index, obtained from on...

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Main Authors: Helen Mavromichalaki, Evangelos Paouris
Format: Article
Language:English
Published: Wiley 2012-01-01
Series:Advances in Astronomy
Online Access:http://dx.doi.org/10.1155/2012/607172
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author Helen Mavromichalaki
Evangelos Paouris
author_facet Helen Mavromichalaki
Evangelos Paouris
author_sort Helen Mavromichalaki
collection DOAJ
description The cosmic ray modulation in relation to solar activity indices and heliospheric parameters during the period January 1996–October 2011, covering the solar cycle 23 and the ascending phase of solar cycle 24, is studied. The new perspective of this contribution is that the CME-index, obtained from only the CMEs with angular width greater than 30 degrees, gives much better results than in previous works. The proposed model for the calculation of the modulated cosmic ray intensity obtained from the combination of solar indices and heliospheric parameters gives a very satisfactory value of the standard deviation. The best reproduction of the cosmic ray intensity is obtained by taking into account solar and interplanetary indices such as sunspot number, interplanetary magnetic field, CME-index, and heliospheric current sheet tilt. The standard deviation between the observed and calculated values is about 6.63% for the solar cycle 23 and 4.13% for the ascending part of solar cycle 24.
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spelling doaj-art-f2e5b46416a4416e96d0a0236bc80a602025-02-03T01:13:13ZengWileyAdvances in Astronomy1687-79691687-79772012-01-01201210.1155/2012/607172607172Long-Term Cosmic Ray Variability and the CME-IndexHelen Mavromichalaki0Evangelos Paouris1Faculty of Physics, National and Kapodistrian University of Athens, Zografos, 15784 Athens, GreeceFaculty of Physics, National and Kapodistrian University of Athens, Zografos, 15784 Athens, GreeceThe cosmic ray modulation in relation to solar activity indices and heliospheric parameters during the period January 1996–October 2011, covering the solar cycle 23 and the ascending phase of solar cycle 24, is studied. The new perspective of this contribution is that the CME-index, obtained from only the CMEs with angular width greater than 30 degrees, gives much better results than in previous works. The proposed model for the calculation of the modulated cosmic ray intensity obtained from the combination of solar indices and heliospheric parameters gives a very satisfactory value of the standard deviation. The best reproduction of the cosmic ray intensity is obtained by taking into account solar and interplanetary indices such as sunspot number, interplanetary magnetic field, CME-index, and heliospheric current sheet tilt. The standard deviation between the observed and calculated values is about 6.63% for the solar cycle 23 and 4.13% for the ascending part of solar cycle 24.http://dx.doi.org/10.1155/2012/607172
spellingShingle Helen Mavromichalaki
Evangelos Paouris
Long-Term Cosmic Ray Variability and the CME-Index
Advances in Astronomy
title Long-Term Cosmic Ray Variability and the CME-Index
title_full Long-Term Cosmic Ray Variability and the CME-Index
title_fullStr Long-Term Cosmic Ray Variability and the CME-Index
title_full_unstemmed Long-Term Cosmic Ray Variability and the CME-Index
title_short Long-Term Cosmic Ray Variability and the CME-Index
title_sort long term cosmic ray variability and the cme index
url http://dx.doi.org/10.1155/2012/607172
work_keys_str_mv AT helenmavromichalaki longtermcosmicrayvariabilityandthecmeindex
AT evangelospaouris longtermcosmicrayvariabilityandthecmeindex