Comparison of cosmic ray cutoff rigidities as calculated with two empirical magnetospheric models for the extreme event of November 2003

Cosmic ray cutoff rigidities control the access of CR particles to any location in the magnetosphere, and, hence, they are an important factor of space weather. The accuracy of determining geomagnetic cutoff rigidities is closely connected with the magnetospheric model used for the calculations. Using the trajectory tracing method and the Tsyganenko magnetospheric Ts01 and Ts04 models, we estimated changes in the effective vertical cutoff rigidities for a highly stormy period of November, 2003. The Ts01 and Ts04 models were developed on the basis of the same experimental data. The results of our calculations are compared with the geomagnetic cutoff rigidities obtained by the spectrographic global survey method using the neutron monitor world-wide network data. Our calculations were performed for several stations with quiet cutoff rigidities covering the major part of the cutoffs influenced by the geomagnetic field. Comparison shows that the cutoff rigidities calculated by using the Ts01 and Ts04 models differ by 0.8-0.9 GV during the main phase of the storm.