Abstract
The work includes the development of a method for determining the rigidity of geomagnetic cutoff based on tracing charged particles in the Earth’s magnetic field using the particle-in-cell method, implemented in the Buneman–Boris scheme. To test the method, calculations of the geomagnetic cutoff rigidity were carried out in the field of an ideal dipole and in the field specified by the IGRF model. In the first case, the obtained data were compared with analytical values. The calculation accuracy in this case was 3 MV. In the second case, the penumbra pattern was reproduced at different geographical points for different periods, and the stability of the method to small perturbations of the initial parameters was also investigated. As the main results of the work, maps of geomagnetic cutoff rigidity at the altitudes of low-orbit satellites for different directions in space, as well as their variations from 1900 to 2015, were constructed and analyzed.