- icrc2007@icrc2007.unam.mx
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Contribution Oral
Forbush decreases: Energy dependence of the recovery
Speakers
- Dr. Ilya USOSKIN
Primary authors
- Dr. Ilya USOSKIN (Sodankylä Geophysical Observatory Finland)
Co-authors
- Mr. Teppo JAMSEN (Sodankylä Geophysical Observatory Finland)
- Dr. Gennady KOVALTSOV (Ioffe Phys-tech. Institute, St.Petersburg, Russia)
- Dr. Olga GLADYSHEVA (Ioffe Phys-tech. Institute, St.Petersburg, Russia)
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Abstract content
We presented a statistical study of major Forbush decreases during the last decades,
using cosmic ray data from ground based detectors -- neutron monitors and a muon
detector. We show that, in addition to typical event (e.g., September 2005), there
are several unusual Forbush decreases (e.g., November 2004), which depict unexpected
features:
(1) the recovery time of a Forbush decrease strongly depends on the
mean response energy of the detector;
(2) an over-recovery is observed in the most energetic cosmic ray data (muon detector).
Such a behavior is not expected from the standard theory of a Forbush decrease. Here
we suggest a simple qualitative scenario for the observed phenomenon.
Reference
Proceedings of the 30th International Cosmic Ray Conference; Rogelio Caballero, Juan Carlos D'Olivo, Gustavo Medina-Tanco, Lukas Nellen, Federico A. Sánchez, José F. Valdés-Galicia (eds.); Universidad Nacional Autónoma de México, Mexico City, Mexico, 2008; Vol. 1 (SH), pages 327-330