3-11 July 2007
Merida, Mexico
Mexico/General timezone
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Contribution Oral

Merida, Mexico - Yucatan I (Fiesta Americana)
SH.2.1

Forbush decreases: Energy dependence of the recovery

Speakers

  • Dr. Ilya USOSKIN

Primary authors

Co-authors

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