Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-25T17:46:14.750Z Has data issue: false hasContentIssue false
  • English
  • Français

Cosmic ray modulation by corotating interaction regions

Published online by Cambridge University Press:  01 September 2008

Jaša Čalogović ,
Bojan Vršnak ,
Manuela Temmer  and
Astrid M. Veronig
Jaša Čalogović
Affiliation:
Hvar Observatory, Faculty of Geodesy, Kačićeva 26, HR-10000 Zagreb, Croatia email: [email protected]
Bojan Vršnak
Affiliation:
Hvar Observatory, Faculty of Geodesy, Kačićeva 26, HR-10000 Zagreb, Croatia email: [email protected]
Manuela Temmer
Affiliation:
Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz, Austria
Astrid M. Veronig
Affiliation:
Institute of Physics, University of Graz, Universitätsplatz 5, A-8010 Graz, Austria
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We analyzed the relationship between the ground-based modulation of cosmic rays (CR) and corotating interaction regions (CIRs). Daily averaged data from 8 different neutron monitor (NM) stations were used, covering rigidities from Rc = 0 − 12.91 GeV. The in situ solar wind data were taken from the Advanced Composition Explorer (ACE) database, whereas the coronal hole (CH) areas were derived from the Solar X-Ray Imager onboard GOES-12. For the analysis we have chosen a period in the declining phase of solar cycle 23, covering the period 25 January–5 May 2005. During the CIR periods CR decreased typically from 0.5% to 2%. A cross-correlation analysis showed a distinct anti-correlation between the magnetic field and CR, with the correlation coefficient (r) ranging from −0.31 to −0.38 (mean: −0.36) and with the CR time delay of 2 to 3 days. Similar anti-correlations were found for the solar wind density and velocity characterized by the CR time lag of 4 and 1 day, respectively. The relationship was also established between the CR modulation and the area of the CIR-related CH with the CR time lag of 5 days after the central-meridian passage of CH.

Keywords

(ISM:) cosmic rays(Sun:) solar wind(Sun:) solar-terrestrial relations
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 4 , Symposium S257: Universal Heliophysical Processes , September 2008 , pp. 425 - 427
Copyright
Copyright © International Astronomical Union 2009

References

Hill, S. M. et al. 2005, Solar Phys., 226, 255CrossRefGoogle Scholar
Pizzo, V. J. et al. 2005, Solar Phys., 226, 283CrossRefGoogle Scholar
Richardson, I. G. 2004, Space Sci. Revs, 111 (3), 267CrossRefGoogle Scholar
Stone, E. C., Frandsen, A. M., Mewaldt, R. A., Christian, E. R., Margolies, D., Ormes, J. F., & Snow, F. 1998, Space Sci. Revs, 86, 1CrossRefGoogle Scholar
Temmer, M., Vrsnak, B., & Veronig, M. A. 2007, Solar Phys., 241, 371CrossRefGoogle Scholar
Vršnak, B., Temmer, M., & Veronig, M. A. 2007a, Solar Phys., 240, 331CrossRefGoogle Scholar
Vršnak, B., Temmer, M., & Veronig, M. A. 2007b, Solar Phys., 240, 315CrossRefGoogle Scholar