Effect of the asymmetric magnetosphere on the cosmic ray cut-off rigidity for middle-latitude stations

Threshold cosmic ray cut-off rigidities for vertically incident particles in magnetosphere model field, taking account of internal and external sources, that well agrees with experimental data on magnetic field for Kp=0, 2 and >3, are determined. Calculation results for middle-latitude stations show that cut-off rigidities of main cone experience diurnal variations