ИСТИНА

The method of the analysis of data on vertical rigidities of cosmic rays cutoff is presented based on the particle trajectory calculations in the geomagnetic field described by the Tsyganenko-89 model. The essence of the method consists in the fact that both the experimental data and the calculation results are described in the form of change of their value relative to the values related to IGRF. The value of these relative changes quite certainly depends on the rigidity itself and on the level of geomagnetic field disturbance (the K p-index). The proposed model well describes calculation data and agrees with the results of cutoff rigidity measurements carried out on satellites.