Solar Physics

, Volume 266, Issue 1, pp 173–180

On Mid-Term Periodicities in Cosmic Rays

  • Karel Kudela
  • Helen Mavromichalaki
  • Athanasios Papaioannou
  • Maria Gerontidou
Article

DOI: 10.1007/s11207-010-9598-0

Cite this article as:
Kudela, K., Mavromichalaki, H., Papaioannou, A. et al. Sol Phys (2010) 266: 173. doi:10.1007/s11207-010-9598-0

Abstract

The contributions of quasi-periodic variations of cosmic rays for T>27 days at the primary energies to which neutron monitors are sensitive have a rather complicated character. They were reported in several papers (e.g. Valdés-Galicia, Perez-Enriquez, and Otaola, 1996; Mavromichalaki et al., 2003; Kudela et al., 2002; Caballero and Valdés-Galicia, 2001) from individual stations and for various time intervals covered. The data archive of several neutron monitor stations developed within the NMDB project (www.nmdb.eu) now involves long time series of measurements at neutron monitors situated at different geomagnetic cut-off rigidity positions and at different altitudes. It is updated continuously. Using the daily averages of cosmic-ray intensity at three selected stations within NMDB: i) the temporal evolution of the selected quasi-periodicities, especially those of approximately 1.7 yr, 150 days and 26 – 32 days respectively, until 2008 are reviewed, ii) the similarities of the spectra are checked and iii) the occurrence of quasi-periodicities with those observed in solar, interplanetary and geomagnetic activities (Moussas et al., 2005; Richardson and Cane, 2005) as well as in energetic particles below the atmospheric threshold are discussed (Laurenza et al., 2009).

Keywords

Cosmic raysNeutron monitorsPeriodicities

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  • Karel Kudela
    • 1
  • Helen Mavromichalaki
    • 2
  • Athanasios Papaioannou
    • 2
  • Maria Gerontidou
    • 2
  1. 1.Institute of Experimental Physics Slovak Academy of SciencesKosiceSlovakia
  2. 2.Nuclear and Particle Physics Section, Physics DepartmentUniversity of AthensAthensGreece