Disturbed Magnetosphere On November 7-8, 2004 And Variations Of Cosmic Ray Cutoff Rigidity: Latitude Effects

We have studied the latitude behavior of cosmic ray cutoff rigidity and their sensitivity to B-z and B-y components of the interplanetary magnetic field and geomagnetic activity indices Dst and K-p for different phases of the November 7-8, 2004 strong magnetic storm. Cutoff rigidities have been calculated using two methods: the spectrographic global survey method in which the cutoff rigidity is determined from observational data, acquired by the neutron monitor network, and the method in which particle trajectories are calculated numerically in a model magnetic field of the magnetosphere. We have found that the sensitivity of observed cutoff rigidities to Dst changes with latitude (threshold rigidity of stations) is in antiphase with changes in the sensitivity to B-y. During the recovery phase of the storm, the D-st correlation with B-y is significantly greater than that with B-z, and the K-p correlation with B-z is greater than that with B-y. The B-y component is shown to be a predominant driver of the current systems that determine the Dst evolution during the recovery phase.