Rigidity spectrum of Forbush decrease calculated by neutron monitors data corrected and uncorrected for geomagnetic disturbances

• Published in: Journal of physics. Conference series Vol. 409; no. 1; pp. 12184 - 4
• Main Authors: Alania, M V, Wawrzynczak, A, Sdobnov, V E, Kravtsova, M V
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.01.2013
• Subjects: Cosmic rays; Cut off; Disturbances; Forbush decreases; Galactic cosmic rays; Geomagnetism; Interplanetary magnetic field; Magnetic storms; Mathematical analysis; Monitors; Physics; Rigidity; Temporal logic
• DOI: 10.1088/1742-6596/409/1/012184
• ISSN: 1742-6596; 1742-6588

Forbush decreases (Fd) of the galactic cosmic ray (GCR) intensity and geomagnetic storms are observed almost at the same time. Geomagnetic storm is a reason of significant disturbances of the magnetic cut off rigidity causing the distortion of the time profile of the Fd of the GCR intensity. We show some differences in the temporal changes of the rigidity spectra of Fd calculated by neutron monitors experimental data corrected and uncorrected for the changes of the geomagnetic cut off rigidity. Nevertheless, the general features of the temporal changes of the rigidity spectrum of Fd maintain as it was found in our previous investigations. Namely, at the beginning phase of Fd rigidity spectrum is relatively soft and gradually becomes hard up to reaching the minimum level of the GCR intensity; then the rigidity spectrum gradually becomes soft during the recovery phase of Fd. We also confirm that for the established temporal profiles of the rigidity spectrum of Fd a structural changes of the interplanetary magnetic field turbulence in the range of frequencies, 10−-6÷10−-5 Hz are responsible.